Symptoms

After a recent network outage, task notification is no longer being sent. Email events are working.
 

Diagnoses

Looking at the ConnectionStringEditor.exe and the K2HostServer.exe.config file, it was determined that SmartActions was enabled and EWS was the configured method for sending task notification. Testing the EWS connection string via the EWSTesterTool provided we were able to send an email successfully with the account configured in the self="" node and as such it was not an issue with the sending of emails. Looking at the Computer Management > Services and Application > Message Queueing > Public Queues the 'eventbus' queue appears to have a high count of items. Usually this is a intermediary location where messages are queued up and processed (usually right away) and will be empty most of the time. The earlier items in the 'eventbus' queue have created dates matching when the network outage occurred. It may have been that the network outage contributed to the processing of the eventbus queue.
 

Resolution

Restarting the K2 blackpearl service allowed for the processing of the items in the queue and task notification is now functional.