We have the single server Exchange 2019 CU 8. There is clean installing, isn't migration. Auto-acceptance of resource groups is not work. The msexchangemailboxassistants service starts and stops immediately. Errors 4999 in logs Watson report about to be sent for process id: 16676, with parameters: E1211S, c-RTL-AMD64, 15.02.0792.010, MSExchangeMailboxAssistants, M.Exchange.Assistants, M.E.A.AssistantsRpcServer.RegisterAssistant, SystemArgumentException, 503a-dumptidset, 15.02.0792.010. ErrorReportingEnabled: False And error 7031 The Microsoft Exchange Mailbox Assistant service terminated unexpectedly. This happened once. The next corrective action will be taken after 5000 msec: Restart the service. We need some advices about this problem. Thx.