Troubleshoot domain controller deployment

This article covers detailed methodology on troubleshooting domain controller configuration and deployment.

Applies to:   Windows Server 2022, Windows Server 2019, Windows Server 2016

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Introduction to troubleshooting

Diagram that shows the workflow for troubleshooting domain controller deployment.

Built-in logs for troubleshooting

The built-in logs are the most important instrument for troubleshooting issues with domain controller promotion and demotion. All of these logs are enabled and configured for maximum verbosity by default.

Phase Log
Server Manager or ADDSDeployment Windows PowerShell operations - %systemroot%\debug\dcpromoui.log

- %systemroot%\debug\dcpromoui.log*

Installation/Promotion of the domain controller - %systemroot%\debug\dcpromo.log

- %systemroot%\debug\dcpromo*.log

- Event Viewer\Windows Logs\System

- Event Viewer\Windows Logs\Application

- Event Viewer\Applications and Services Logs\Directory Service

- Event Viewer\Applications and Services Logs\File Replication Service

- Event Viewer\Applications and Services Logs\DFS Replication

Forest or domain upgrade - %systemroot%\debug\adprep\<datetime>\adprep.log

- %systemroot%\debug\adprep\<datetime>\csv.log

- %systemroot%\debug\adprep\<datetime>\dspecup.log

- %systemroot%\debug\adprep\<datetime>\ldif.log*

Server Manager ADDSDeployment Windows PowerShell deployment engine - Event Viewer\Applications and Services Logs\Microsoft\Windows\DirectoryServices-Deployment\Operational
Windows Servicing - %systemroot%\Logs\CBS\*

- %systemroot%\servicing\sessions\sessions.xml

- %systemroot%\winsxs\poqexec.log

- %systemroot%\winsxs\pending.xml

Tools and commands for troubleshooting domain controller configuration

To troubleshoot issues not explained by the logs, use the following tools as a starting point:

General methodology for troubleshooting domain controller configuration

  1. Did a syntax issue cause the error?

    1. Did you mistype or forget to provide an argument to ADDSDeployment Windows PowerShell? For example, if using ADDSDeployment Windows PowerShell, did you forget to add required argument -domainname with a valid name?
    2. Examine the Windows PowerShell console output carefully to see exactly why it's failing to parse the command-line provided.
  2. Is the error a prerequisite failure?

    1. Many errors that used to appear as fatal promotion results are now prevented by the prerequisite checker.
    2. Examine the text of the prerequisite errors carefully, they provide the necessary guidance to resolve most issues, as they're controlled scenarios.
  3. Is the error in promotion and therefore fatal?

    1. Examine the results carefully: many errors have explanations such as bad passwords, network name resolution, or critical offline domain controllers.

    2. Examine the Dcpromoui.log and dcpromo.log for the errors shown in the output, then work backwards from them to see indications of why the failure occurred.

      1. Always compare to a working sample log
      2. Examine the ADPrep logs for errors only if the results indicate a problem extending the schema or preparing the forest or domain.
      3. Examine the DirectoryServices-Deployment event log for errors only if the Dcpromoui.log lacks detail or ends arbitrarily due to an unhandled exception in the configuration process.
    3. Examine the Directory Services, System, and Application event logs for other indicators of a configuration issue. Often, the domain controller promotion is just a symptom of other network misconfiguration that would affect all distributed systems.

    4. Use dcdiag.exe and repadmin.exe to validate the overall forest health and indicate subtle misconfigurations that may prevent further domain controller promotion.

    5. Use AutoRuns.exe, Task Manager, or MSinfo32.exe to examine the computer for third party software that may be interfering.

      Remove third party software (don't disable the software; that doesn't prevent drivers loading).

    6. Install NetMon 3.4 on the computer that fails to promote as well the replication partner domain controller and analyze the promotion process with double-sided network captures.

      1. Compare this to your working lab environment to understand what a healthy promotion looks like and where it's failing.
      2. At this point, the errors are likely with the forest objects, nondefault security changes, or the network, and this new domain controller is a victim of misconfigurations in DNS, firewalls, host intrusion protection software, or other outside factors.

Troubleshooting events and error messages

Domain controller promotion and demotion always return a code at the end of operation and unlike most programs, don't return zero for success. To see the code at the end of a domain controller configuration, you have several options:

  1. When using Server Manager, examine the promotion results in the 10 seconds prior to automatic reboot.

  2. When using ADDSDeployment Windows PowerShell, examine the promotion results in the 10 seconds prior to automatic reboot. Alternatively, choose not to restart automatically on completion. You should add the format-list pipeline to make the output easier to read. For example:

    Install-addsdomaincontroller <options> -norebootoncompletion:$true | format-list
    

    Errors in prerequisite validation and verification don't continue on to a reboot, so they're visible in all cases. For example:

    Screenshot of the errors in prerequisite validation and verification.

  3. In any scenario, examine the dcpromo.log and dcpromoui.log.

    Note

    Some of the errors listed below are no longer possible due to operating system and domain controller configuration changes in later operating systems. The new ADDSDeployment Windows PowerShell codes also prevents certain errors, but the dcpromo.exe /unattend does not; this is another compelling reason to switch all of your current automation from the deprecated DCPromo to ADDSDeployment Windows PowerShell.

Promotion and demotion success codes

Error code Explanation Note
1 Exit, success You still must reboot, this just notes that the automatic restart flag was removed.
2 Exit, success, need to reboot
3 Exit, success, with a noncritical failure Typically seen when returning the DNS Delegation warning. If not configuring DNS delegation, use:

-creatednsdelegation:$false.

4 Exit, success, with a noncritical failure, need to reboot Typically seen when returning the DNS Delegation warning. If not configuring DNS delegation, use:

-creatednsdelegation:$false.

Promotion and demotion failure codes

Promotion and demotion return the following failure message codes. There's also likely to be an extended error message; always read the entire error carefully, not just the numeric portion.

Error code Explanation Suggested resolution
11 Domain controller promotion is already running Don't run more than one instance of domain controller promotion at the same time for the same target computer.
12 User must be administrator Logon as a member of the built-in Administrators group and ensure you're elevating with UAC.
13 Certification Authority is installed You can't demote this domain controller, as it's also a Certification Authority. Don't remove the CA before you carefully inventory its usage. If it's issuing certificates, removing the role will cause an outage. Running CAs on domain controllers is discouraged.
14 Running in safe-boot mode Boot the server into normal mode.
15 Role change is in progress or needs reboot You must restart the server (due to prior configuration changes) before promotion.
16 Running on wrong platform Not likely to get this error.
17 No NTFS 5 drives exist This error isn't possible in Windows Server 2012, which requires at least the %systemdrive% be formatted with NTFS.
18 Not enough space in windir Free up space on the %systemdrive% volume using cleanmgr.exe.
19 Name change pending, needs reboot Reboot the server.
20 Computer name is invalid syntax Rename the computer with a valid name.
21 This domain controller holds FSMO roles, is a GC, and/or is a DNS server Add -demoteoperationmasterrole when using -forceremoval.
22 TCP/IP needs to be installed or isn't functioning Verify computer has TCP/IP configured, bound, and working correctly.
23 DNS client needs to be configured first Set a primary DNS server when adding a new domain controller to a domain.
24 Supplied credentials are invalid or missing required elements Verify your user name and password is correct.
25 Domain controller for the specified domain couldn't be located Validate DNS client settings, firewall rules.
26 List of domains couldn't be read from the forest Validate DNS client settings, LDAP functionality, firewall rules.
27 Missing domain name Specify a domain when promoting or demoting.
28 Bad domain name Choose a different, valid DNS domain name when promoting.
29 Parent domain doesn't exist Verify the parent domain specified when creating a new child domain or tree domain.
30 Domain not in forest Verify the domain name provided.
31 Child Domain already exists Specify a different domain name.
32 Bad NetBIOS domain name Specify a valid NetBIOS domain name.
33 Path to the IFM files is invalid Validate your path to the Install From Media folder.
34 The IFM database is bad Use the correct Install From Media for this operating system and role (same operating system version, same type of domain controller - RODC versus RWDC).
35 Missing SYSKEY The Install from Media is encrypted and you must provide a valid SYSKEY to use it.
37 Path for NTDS Database or its logs is invalid Change path of Database and Logs to a fixed NTFS volume, not a mapped drive or UNC path.
38 Volume doesn't have enough space for NTDS database or logs Free up space using cleanmgr.exe, add more disk space, manually clear space by moving unnecessary data elsewhere.
39 Path for SYSVOL is invalid Change path of SYSVOL folder to a fixed NTFS volume, not a mapped drive or UNC path.
40 Invalid site name Provide a site name that exists.
41 Need to specify a password for safe-mode Provide a password for the DSRM account, it can't be blank no matter how the password policy is configured.
42 Safe-mode password doesn't meet criteria (promotion only) Provide a password for the DSRM account that meets the password policy's configured rules.
43 Admin password doesn't meet criteria (demotion only) Provide a password for the local administrator account that meets the password policy's configured rules.
44 The specified name for the forest is invalid Specify a valid forest root DNS domain name.
45 A forest with the specified name already exists Choose a different forest root DNS domain name.
46 The specified name for the tree is invalid Specify a valid tree DNS domain name.
47 A tree with the specified name already exists Choose a different tree DNS domain name.
48 The tree name doesn't fit into the forest structure Choose a different tree DNS domain name.
49 The specified domain doesn't exist Verify your typed domain name.
50 During demote, last domain controller was detected even though it isn't, or last domain controller was specified, but it isn't Don't specify Last Domain Controller in the Domain (-lastdomaincontrollerindomain) unless it's true. Use -ignorelastdcindomainmismatch to override if this is truly the last domain controller and there's phantom domain controller metadata.
51 App partitions exist on this domain controller Specify to Remove Application Partitions (-removeapplicationpartitions).
52 Required command-line argument is missing (that is, an answer file must be specified on the command-line) Only seen with dcpromo /unattend, which is deprecated. See older documentation.
53 The promotion/demotion failed, machine must be rebooted to clean up Examine the extended error and logs.
54 The promotion/demotion failed Examine the extended error and logs.
55 The promotion/demotion was canceled by the user Examine the extended error and logs.
56 The promotion/demotion was canceled by the user, machine must be rebooted to clean up Examine the extended error and logs.
58 A site name must be specified during RODC promotion You must specify a site for an RODC, it will not automatically detect one like an RWDC.
59 During demote, this domain controller is the last DNS server for one of its zones Specify that this is the Last DNS Server in the Domain or use -ignorelastdnsserverfordomain.
60 A domain controller running Windows Server 2008 or later must be present in the domain in order to promote RODC Promote at least one Windows Server 2008 or later model writable domain controller.
61 You can't install Active Directory Domain Services with DNS in an existing domain that doesn't already host DNS Not possible to get this error.
62 Answer file doesn't have a [DCInstall] section Only seen with dcpromo /unattend, which is deprecated. See older documentation.
63 Forest functional level is below windows server 2003 Raise the forest functional level to at least Windows Server 2003 Native. Windows 2000 and Windows NT 4.0 are no longer supported operating systems.
64 Promo failed because component binary detection failed Install the AD DS role.
65 Promo failed because component binary installation failed Install the AD DS role.
66 Promo failed because operating system detection failed Examine the extended error and logs; the server is failing to return its operating system version. It's likely that the computer will need to be reinstalled, as its overall health is highly suspect.
68 Replication partner is invalid Use repadmin.exe or the Get-ADReplication\* Windows PowerShell to validate partner domain controller health.
69 Required Port is already in use by some other application Use netstat.exe -anob to locate processes that are incorrectly assigned to reserved AD DS ports.
70 The forest root domain controller must be a GC Only seen with dcpromo /unattend, which is deprecated. See older documentation.
71 DNS server is already installed Don't specify to install DNS (-installDNS) if the DNS service is already installed.
72 Computer is running Remote Desktop Services in nonadmin mode You can't promote this domain controller, as it's also a RDS server configured for more than two admin users. Don't remove RDS before you carefully inventory its usage. If it's being used by applications or end-users, removal will cause an outage.
73 The specified forest functional level is invalid. Specify a valid forest functional level.
74 The specified domain functional level is invalid. Specify a valid domain functional level.
75 Unable to determine the default password replication policy. Validate that the RODC password replication policy exists and is accessible.
76 Specified replicated/non-replicated security groups are invalid Validate that you have typed in valid domain and user accounts when specifying a password replication policy.
77 The specified argument is invalid Examine the extended error and logs.
78 Failed to examine Active Directory Forest Examine the extended error and logs.
79 RODC can't be promoted because rodcprep has not been performed Use Windows Server 2012 to prepare the forest or use adprep.exe /rodcprep.
80 Domainprep has not been performed Use Windows Server 2012 to prepare the domain or use adprep.exe /domainprep.
81 Forestprep has not been performed Use Windows Server 2012 to prepare the forest or use adprep.exe /forestprep.
82 Forest schema mismatch Use Windows Server 2012 to prepare the forest or use adprep.exe /forestprep.
83 Unsupported SKU Not likely to get this error.
84 Unable to detect a domain controller account Validate that existing domain controllers have correct user account control attribute set.
85 Unable to select a domain controller account for stage 2 Returned if you specify "Use Existing Account" but either no account found or there's an error during account lookup. Ensure you provided the correct RODC staged account.
86 Need to run stage 2 promotion Returned if you promote an additional domain controller but an existing account exists and "Allow Reinstall" wasn't specified.
87 A domain controller account of conflicting type exists Rename the computer before promoting, if not trying to attach to an unoccupied domain controller. You must attach to the unoccupied domain controller account using -useexistingaccount and the correct read-only or writable argument, depending on account type.
88 The specified server admin isn't valid You specified an invalid account for RODC admin delegation. Verify that the account specified is a valid user or group.
89 RID master for the specified domain is offline. Use netdom.exe query fsmo to detect the RID master. Bring it online and make it accessible to the domain controller you're promoting.
90 Domain naming master is offline. Use netdom.exe query fsmo to detect the domain naming master. Bring it online and make it accessible to the domain controller you're promoting.
91 Failed to detect if the process is wow64 Not possible to get this error anymore, the operating system is 64-bit.
92 Wow64 process isn't supported Not possible to get this error anymore, the operating system is 64-bit.
93 Domain controller service isn't running for nonforceful demotion Start the AD DS service.
94 Local admin password doesn't meet requirement: either blank or not required Provide a nonblank password and ensure that the local password policy requires a password.
95 Can't demote last Windows Server 2008 or later domain controller in the domain where live RODCs exist You must first demote all RODCs before you can demote all Windows Server 2008 or later writable domain controllers.
96 Unable to uninstall DS binaries Only seen with dcpromo /unattend, which is deprecated. See older documentation.
97 Forest functional level version higher than that of the child domain operating system Provide a child domain functional the same or higher than the forest functional level.
98 Component binary install/uninstall is in progress. Only seen with dcpromo /unattend, which is deprecated. See older documentation.
99 Forest functional level is too low (error is Windows Server 2012 only) Raise the forest functional level to at least Windows Server 2003 native. Windows 2000 and Windows NT 4.0 are no longer supported operating systems.
100 Domain functional level is too low (error is Windows Server 2012 only) Raise the domain functional level to at least Windows Server 2003 native. Windows 2000 and Windows NT 4.0 are no longer supported operating systems.

Known issues and common support scenarios

The following are common issues seen during the Windows Server 2012 development process. All of these issues are "by design" and have either a valid workaround or more appropriate technique to avoid them in the first place. Many of these behaviors are identical in Windows Server 2008 R2 and older operating systems, but the rewrite of AD DS deployment brings heightened sensitivity to issues.

Issue Demoting a domain controller leaves DNS running with no zones
Symptoms Server still responds to DNS requests but has no zone information
Resolution and Notes When removing the AD DS role, also remove the DNS Server role or set the DNS Server service to disabled. Remember to point the DNS client to another server than itself. If using Windows PowerShell, run the following after you demote the server:

Code - uninstall-windowsfeature dns

or

Code - set-service dns -starttype disabled
stop-service dns

Issue Promoting a Windows Server 2012 into an existing single-label domain doesn't configure updatetopleveldomain=1 or allowsinglelabeldnsdomain=1
Symptoms DNS dynamic record registration doesn't occur
Resolution and Notes Set these values using the Netlogon and DNS group policies. Microsoft began blocking single-label domain creation in Windows Server 2008; you can use ADMT or the Domain Rename Tool to change to an approved DNS domain structure.
Issue Demotion of last domain controller in a domain fails if there are pre-created, unoccupied RODC accounts
Symptoms Demotion fails with message:

Dcpromo.General.54

Active Directory Domain Services couldn't find another Active Directory Domain Controller to transfer the remaining data in directory partition CN=Schema,CN=Configuration,DC=corp,DC=contoso,DC=com.

"The format of the specified domain name is invalid."

Resolution and Notes Remove any remaining pre-created RODC accounts before demoting a domain, using Dsa.msc or Ntdsutil.exe metadata cleanup.
Issue Automated forest and domain preparation doesn't run GPPREP
Symptoms Cross-domain planning functionality for Group Policy, Resultant Set of Policy (RSOP) Planning Mode, requires updated file system and Active Directory permissions for existing GP. Without Gpprep, you can't use RSOP Planning across domains.
Resolution and Notes Run adprep.exe /gpprep manually for all domains that weren't previously prepared for Windows Server 2003, Windows Server 2008, or Windows Server 2008 R2. Administrators should run GPPrep only once in the history of a domain, not with every upgrade. It isn't run by automatic adprep because if you have already set adequate custom permissions, it would cause all SYSVOL contents to re-replicate on all domain controllers.
Issue Install from media fails to verify when pointing to a UNC path
Symptoms Error returned:

Code - Couldn't validate media path. Exception calling "GetDatabaseInfo" with "2" arguments. The folder isn't valid.

Resolution and Notes You must store IFM files on a local disk, not a remote UNC path. This intentional block prevents partial server promotion due to a network interruption.
Issue DNS delegation warning shown twice during domain controller promotion
Symptoms Warning returned twice when promoting using ADDSDeployment Windows PowerShell:

Code - A delegation for this DNS server can't be created because the authoritative parent zone can't be found or it doesn't run Windows DNS server. If you're integrating with an existing DNS infrastructure, you should manually create a delegation to this DNS server in the parent zone to ensure reliable name resolution from outside the domain. Otherwise, no action is required.

Resolution and Notes Ignore. ADDSDeployment Windows PowerShell shows the warning first during prerequisite checking, then again during configuration of the domain controller. If you don't wish to configure DNS delegation, use argument:

Code - -creatednsdelegation:$false

Don't skip the prerequisite checks in order to suppress this message.

Issue Specifying UPN or nondomain credentials during configuration returns misleading errors
Symptoms Server Manager returns error:

Code - Exception calling "DNSOption" with "6" Arguments

ADDSDeployment Windows PowerShell returns error:

Code - Verification of user permissions failed. You must supply the name of the domain to which this user account belongs.

Resolution and Notes Ensure you're providing valid domain credentials in the form of <domain>\<user>.
Issue Removing the DirectoryServices-DomainController role using Dism.exe leads to unbootable server
Symptoms If using Dism.exe to remove the AD DS role before demoting a domain controller gracefully, the server no longer boots normally and shows error:

Code - Status: 0x000000000
Info: An unexpected error has occurred.

Resolution and Notes Boot into Directory Services Repair Mode using Shift+F8. Add the AD DS role back, and then forcibly demote the domain controller. Alternatively, restore the System State from backup. Don't use Dism.exe for AD DS role removal; the utility has no knowledge of domain controllers.
Issue Installing a new forest fails when setting forestmode to Win2012
Symptoms Promotion using ADDSDeployment Windows PowerShell returns error:

Code - Test.VerifyDcPromoCore.DCPromo.General.74

Verification of prerequisites for Domain Controller promotion failed. The specified domain functional level is invalid.

Resolution and Notes Don't specify a forest functional mode of Win2012 without also specifying a domain functional mode of Win2012. Here's an example that will work without errors:

Code - -forestmode Win2012 -domainmode Win2012

Issue Selecting Verify in the Install from Media selection area appears to do nothing
Symptoms When you specify a path to an IFM folder, selecting the Verify button never returns a message or appears to do anything.
Resolution and Notes The Verify button only returns errors if there are issues. Otherwise, it makes the Next button selectable if you have provided an IFM path. You must select Verify to proceed if you have selected IFM.
Issue Demoting with Server Manager doesn't provide feedback until completed.
Symptoms When using Server Manager to remove the AD DS role and demote a domain controller, there's no ongoing feedback given until the demotion completes or fails.
Resolution and Notes This is a limitation of Server Manager. For feedback, use ADDSDeployment Windows PowerShell cmdlet:

Code - Uninstall-addsdomaincontroller

Issue Install from Media Verify doesn't detect that RODC media provided for writable domain controller, or vice versa.
Symptoms When promoting a new domain controller using IFM and providing incorrect media to IFM - such as RODC media for a writable domain controller, or RWDC media for an RODC - the Verify button doesn't return an error. Later, promotion fails with error:

Code - An error occurred while trying to configure this machine as a domain controller.
The Install-From-Media promotion of a Read-Only DC can't start because the specified source database isn't allowed. Only databases from other RODCs can be used for IFM promotion of a RODC.

Resolution and Notes Verify only validates the overall integrity of IFM. Don't provide the wrong IFM type to a server. Restart the server before you attempt promotion again with the correct media.
Issue Promoting an RODC into a precreated computer account fails
Symptoms When using ADDSDeployment Windows PowerShell to promote a new RODC with a staged computer account, receive error:

Code - Parameter set can't be resolved using the specified named parameters.
InvalidArgument: ParameterBindingException
+ FullyQualifiedErrorId : AmbiguousParameterSet,Microsoft.DirectoryServices.Deployment.PowerShell.Commands.Install

Resolution and Notes Don't provide parameters already defined already on a precreated RODC account. These include:

Code -
-readonlyreplica
-installdns
-donotconfigureglobalcatalog
-sitename
-installdns

Issue Deselecting/selecting "Restart each destination server automatically if required" does nothing
Symptoms If selecting (or not selecting) the Server Manager option Restart each destination server automatically if required when demoting a domain controller through role removal, the server always restarts, regardless of choice.
Resolution and Notes This is intentional. The demotion process restarts the server regardless of this setting.
Issue Dcpromo.log shows "[error] setting security on server files failed with 2"
Symptoms Demotion of a domain controller completes without issues, but examination of the dcpromo log shows error:

Code - [error] setting security on server files failed with 2

Resolution and Notes Ignore, error is expected and cosmetic.
Issue Prerequisite adprep check fails with error "Unable to perform Exchange schema conflict check"
Symptoms When attempting to promote a Windows Server 2012 domain controller into an existing Windows Server 2003, Windows Server 2008, or Windows Server 2008 R2 forest, prerequisite check fails with error:

Code - Verification of prerequisites for AD prep failed. Unable to perform Exchange schema conflict check for domain <domain name> (Exception: the RPC server is unavailable)

The adprep.log shows error:

Code - Adprep couldn't retrieve data from the server <domain controller>

through Windows Management Instrumentation (WMI).

Resolution and Notes The new domain controller can't access WMI through DCOM/RPC protocols against the existing domain controllers. To date, there have been three causes for this:

- A firewall rule blocks access to the existing domain controllers.
- The NETWORK SERVICE account is missing from the "Logon as a service" (SeServiceLogonRight) privilege on the existing domain controllers.
- NTLM is disabled on domain controllers, using security policies described in Introducing the Restriction of NTLM Authentication.

Issue Creating a new AD DS forest always shows DNS warning
Symptoms When creating a new AD DS forest and creating the DNS zone on the new domain controller for itself, you always receive warning message:

Code - An error was detected in the DNS configuration.
None of the DNS servers used by this computer responded within the timeout interval.
(error code 0x000005B4 "ERROR_TIMEOUT")

Resolution and Notes Ignore. This warning is intentional on the first domain controller in the root domain of a new forest, in case you intended to point to an existing DNS server and zone.
Issue Windows PowerShell -whatif argument returns incorrect DNS server information
Symptoms If you use the -whatif argument when configuring a domain controller with implicit or explicit -installdns:$true, the resulting output shows:

Code - DNS Server: No

Resolution and Notes Ignore. DNS is installed and configured correctly.
Issue After promotion, logon fails with "Not enough storage is available to process this command"
Symptoms After you promote a new domain controller and then log off and attempt to log on interactively, you receive error:

Code - Not enough storage is available to process this command

Resolution and Notes The domain controller wasn't rebooted after promotion, either due to an error or because you specified the ADDSDeployment Windows PowerShell argument -norebootoncompletion. Restart the domain controller.
Issue The Next button isn't available on the Domain Controller Options page
Symptoms Even though you have set a password, the Next button on the Domain Controller Options page in Server Manager isn't available. There's no site listed in the Site name menu.
Resolution and Notes You have multiple AD DS sites and at least one is missing subnets; this future domain controller belongs to one of those subnets. You must manually select the subnet from the Site name dropdown menu. You should also review all AD sites using DSSITE.MSC or use the following Windows PowerShell command to find all sites missing subnets:

Code - "get-adreplicationsite -filter * -property subnets | where-object {!$_.subnets -eq "*"} | format-table name"

Issue Promotion or demotion fails with message "the service can't be started"
Symptoms If you attempt promotion, demotion, or cloning of a domain controller you receive error:

Code - The service can't be started, either because it's disabled or it has no enabled devices associated with it" (0x80070422)

The error may be interactive, an event, or written to a log like dcpromoui.log or dcpromo.log.

Resolution and Notes The DS Role Server service (DsRoleSvc) is disabled. By default, this service is installed during AD DS role installation and set to a Manual start type. Don't disable this service. Set it back to Manual and allow the DS role operations to start and stop it on demand. This behavior is by design.
Issue Server Manager still warns that you need to promote DC
Symptoms If you promote a domain controller using the deprecated dcpromo.exe /unattend or upgrade an existing Windows Server 2008 R2 domain controller in place to Windows Server 2012, Server Manager still shows the post-deployment configuration task Promote this server to a domain controller.
Resolution and Notes select the post-deployment warning link and the message will disappear for good. This behavior is cosmetic and expected.
Issue Server Manager deployment script missing role installation
Symptoms If you promote a domain controller using Server Manager and save the Windows PowerShell deployment script, it doesn't include the role installation cmdlet and arguments (install-windowsfeature -name ad-domain-services -includemanagementtools). Without the role, the DC can't be configured.
Resolution and Notes Manually add that cmdlet and arguments to any scripts. This behavior is expected and by design.
Issue Server Manager deployment script isn't named PS1
Symptoms If you promote a domain controller using Server Manager and save the Windows PowerShell deployment script, the file is named with a random temporary name and not as a PS1 file.
Resolution and Notes Manually rename the file. This behavior is expected and by design.
Issue Dcpromo /unattend allows unsupported functional levels
Symptoms If you promote a domain controller using dcpromo /unattend with the following sample answer file:

Code -

[DCInstall]
NewDomain=Forest

ReplicaOrNewDomain=Domain

NewDomainDNSName=corp.contoso.com

SafeModeAdminPassword=Safepassword@6

DomainNetbiosName=corp

DNSOnNetwork=Yes

AutoConfigDNS=Yes

RebootOnSuccess=NoAndNoPromptEither

RebootOnCompletion=No

DomainLevel=0

ForestLevel=0

Promotion fails with the following errors in the dcpromoui.log:

Code - dcpromoui EA4.5B8 0089 13:31:50.783 Enter CArgumentsSpec::ValidateArgument DomainLevel

dcpromoui EA4.5B8 008A 13:31:50.783 Value for DomainLevel is 0

dcpromoui EA4.5B8 008B 13:31:50.783 Exit code is 77

dcpromoui EA4.5B8 008C 13:31:50.783 The specified argument is invalid.

dcpromoui EA4.5B8 008D 13:31:50.783 closing log

dcpromoui EA4.5B8 0032 13:31:50.830 Exit code is 77

Level 0 is Windows 2000, which isn't supported in Windows Server 2012.

Resolution and Notes Don't use the deprecated dcpromo /unattend and understand that it allows you to specify invalid settings that later fail. This behavior is expected and by design.
Issue Promotion "hangs" at creating NTDS settings object, never completes
Symptoms If you promote a replica DC or RODC, the promotion reaches "creating NTDS settings object" and never proceeds or completes. The logs stop updating as well.
Resolution and Notes This is a known issue caused by providing credentials of the built-in local Administrator account with a matching password to the built-in domain Administrator account. This causes a failure down in the core setup engine that doesn't error, but instead waits indefinitely (quasi-loop). This is expected - albeit undesirable - behavior.

To fix the server:

1. Reboot it.

1. In AD, delete that server's member computer account (it will not yet be a DC account)

2. On that server, forcibly disjoin it from the domain

3. On that server, remove the AD DS role.

4. Reboot

5. Readd the AD DS role and reattempt promotion, ensuring that you always provide the <domain>\<admin> formatted credentials to DC promotion and not just the built-in local administrator account.