The coordinator has stopped and agents in a second domain are inactive.
SQL error (121) A transport-level error has occurred when receiving results from the server /(provider: TCP Provider, error: 0 - The semaphore timeout period has expired./) is found in the Coordinator log (C:\Program Files\Quest Software\ChangeAuditor\Service\ChangeAuditor.Service.exe.nptlog.
In this case, the Coordinator stopped due to a prolonged disconnection to SQL. The above error most likely points to a network connection error between SQL and the Coordinator.
Restarting the Coordinator should allow agents to connect again. If not check for SQL connectivity.