Report Server Windows Service (MSSQLServer) 107
The Report Server Windows service (MSSQLSERVER) cannot connect to the report server database. This error occurs when a service restarts. It occurs if the SQL Server Database Engine service (MSSQLSERVER) is not running when the Report Server Windows service starts.
It also occurs if you do not use the Reporting Services Configuration tool to modify the Report Server Windows service account (for example, if you use Services in Administration Tools) and you restart the service.
It can also occur if the account used to run the service no longer has permissions on the database.