Details: System.Activities.Statements.WorkflowTerminatedException: Could not load file or assembly 'Microsoft.Exchange.WebServices, Version=15.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.
I have make sure the Microsoft Exchange Web Services Manged API is loaded on servers, did IISReset and still no joy. I can send email with out of the box workflow with no issue.