When trying to log into FTKC 7.6 SP2, you get a message on the screen that says the credentials are invalid, but they are the same ones you have always used.
When looking at the log file in C:\ProgramData\Documents\AccessData\AccessDataLogs, you see an error message similar to this-
2023-03-08 12:47:48,511 [*Initialization Thread] ERROR eDiscovery.BusinessComponents.Scheduling.Scheduler [(null)] - (null) SetDateSetting().
System.Data.Entity.Infrastructure.DbUpdateException: An error occurred while updating the entries. See the inner exception for details. ---> System.Data.Entity.Core.UpdateException: An error occurred while updating the entries. See the inner exception for details. ---> System.Data.SqlClient.SqlException: The transaction log for database 'ADG' is full due to 'LOG_BACKUP'.
1. Set the Recover Model for the ADG DB to Simple. Normally it is set to Full
2. Right click on the ADG DB again and selected Tasks, Shrink, FILES. Do not select Database.
3. In the Shrink File screen, select File Type and chose LOG.
4. Make sure the Release unused space is selected and click OK.
After that, make sure to return the ADG Recovery Model back to FULL.
Return to FTKC and see you the users can now log in.
In two separate instances, I have seen that error cause trouble with the users being able to log in, even when using the main administrator account created the first time DBConfig was run.