A licensing error occurred while the client was attempting to connect. (Licensing timed out)

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Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Cause

If you are using Internet Protocol security (IPsec) to help protect traffic over TCP between clients and terminal servers, then packet fragmentation might occur. As a result, some packets might not reach their destinations, and client connections to terminal servers might fail.

Solution

Configure IPsec to help protect traffic over UDP rather than over TCP, as described in Define IPSec Policies (https://go.microsoft.com/fwlink/?LinkID=48889).

Cause

If there is a firewall between the clients and terminal servers, packets might be fragmented due to the size of the maximum transmission unit (MTU) that can be transmitted over the network. As a result, the packet fragments might be dropped or received out of order.

Solution

Verify that the maximum transmission unit (MTU) that can be transmitted over the network is sufficient by running the ping command with the -f (don’t fragment) parameter as follows:

ping -l 1472 -f <Destination_IP_Address>

If the MTU is not sufficient, you can change the MTU on the router or you can configure the computers to use a smaller MTU by modifying the registry. You can configure the computers to use a smaller MTU by creating a new MTU registry key entry and setting the value to 576 (or a larger value if appropriate, if the MTU is larger) or by creating a new EnablePTMUDiscovery registry key entry and setting the value to 0. However, note that Windows Server 2003 And Windows 2000 TCP/IP use PMTU detection by default and query the NIC driver to determine the local MTU that is supported. Therefore, modifying the MTU parameter is generally not necessary and might result in reduced performance.

Warning

Incorrectly editing the registry may severely damage your system. Before making changes to the registry, you should back up any valued data on the computer.

Create a new MTU registry key and set it to 576 (or a larger value)

  1. Open Registry Editor. To open Registry Editor, click Start, click Run, type regedit, and then click OK.

  2. Locate, and then click, the following key in the registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters\Interfaces\<Interface_GUID>

  3. Create a new DWORD registry entry called MTU.

  4. Set the value to 576 (or a larger value, if appropriate).

Create an EnablePMTUDiscovery registry key and set it to 0

  1. Open Registry Editor. To open Registry Editor, click Start, click Run, type regedit, and then click OK.

  2. Locate, and then click, the following key in the registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters

  3. Create a new DWORD registry entry called EnablePMTUDiscovery.

  4. Set the value to 0.