Symptoms

1. After assigning a task, users do not receive a task notification email.
2. Email events, however, do work.
 

Diagnoses

A. Error in logs is showing the following:

"1533851","2015-01-12 12:52:41","Error","MessageBus","61003","InitFail","MessageBusService","61003 Failed to start MessageBus service: System.ArgumentNullException: Value cannot be null.
Parameter name: connectionString
at SourceCode.MessageBus.Ews.ExchangeWebServicesConnection..ctor(String connectionString)

The "Value cannot be null" and "Parameter name: connectionString" alludes to how the EWS strings should not be blank.

 

Resolution

Navigate to the K2 Connection String Editor (Your Installation DriveProgram Files (x86)K2 blackpearlHost ServerBinConnectionStringEditor.exe) and make sure that there are EWS connection strings populated in there.

You should see three in the editor:
1. SourceCode.MessageBus.EWS.ExchangeWebServicesConnection
2. SourceCode.MessageBus.EWS.ExchangeWebServicesDestination
3. SourceCode.MessageBus.EWS.ExchangeWebServicesDestination

If you only see 2, however, one of the destinations and the one connection, that should be fine too. The first two should have an email address at the end.

If you click on each of those, make sure that on the right hand side section of the editor that the ConnectionString field is populated.

A. You WILL have to repopulate the SourceCode.MessageBus.Ews.ExchangeWebServicesConnection (or whichever is blank)

B. Then please restart the K2 service (different from an IIS reset), which is from your Start > Administrative Tools > Services > K2 blackpearl server