Symptoms

K2 production no longer is sending out email notifications for assigned tasks. The tasks are being created properly, it is just the outbound email that is not getting created: however, many users rely on those emails. There have been no changes to the K2 environment that I am aware of. There is an error in the K2 server event log as follows that I am guessing is the problem:

61007 Permanent failure sending message: System.Exception: No destinations could send the message at SourceCode.MessageBus.Server.MessageBusRuntime.SourceCode.MessageBus.IMessageDestination.Send(String title, MessageExtendedInformation extended, IEnumerable`1 attachments, MessageBodyReaderr] messageBodies)

 

Diagnoses

The issue was caused by a change on Exchange Configuration that removed alias (svc_k2_server_prd@xyz.com) for K2 Service account (ecrm.workflow@xyz.com) which is the value configured in K2.
 

Resolution

Adding the alias for K2 Service account in Exchange to match the setting in the environment variable exactly resolved the issue.