Symptoms

We have just installed 4.6.11 and everything appears to be working with the exception of the Exchange EWS integration.

We are connecting to an on-prem version of Exchange 2016 and have verified the autodiscovery and EWS URL are working. We also have verified we can login to the email account via web mail and that the account is visible in the global address list.

Here is the error we get in the log
"172356","2016-02-04 09:19:06","Error","MessageBus","61012","ConnectionError","ExchangeWebServicesOrigin","61012 Exception from message source s-k2@concurrency.com: System.InvalidOperationException: The Exchange server responded with the error 'ErrorNonExistentMailbox'.
at SourceCode.MessageBus.Ews.ExchangeWebServicesConnection.EndSyncFolderItems(Object sender, SyncFolderItemsCompletedEventArgs e)","","","CNCY-K2-02:e:Program Files (x86)K2 blackpearlHost ServerBin","172356","029a22dd86614396bc0b003d6ed3a3ca",""

 

Diagnoses

Get-Mailbox powershell command on the exchange server verified that the account had a mailbox. There is an extra property in Exchange 2016 we are currently not supporting that's throwing this error.




 

Resolution

Customer ignored the error and is still able to use the functionality with Exchange 2016.