Symptoms

We are busy with a new PROD environment move and set-up from on-premise to cloud. We are having issues with the EWS AUTO DISCOVER. When running the set-up and the test link is clicked, a message is given that it cannot be validated (see attachment EWS 1). If we ignore the message and kick off a process, an error message is received (see attachment EWS 2).
 

Diagnoses

Autodiscover MUST be enabled when using Exchange Online. See http://msdn.microsoft.com/en-us/library/exchange/gg194011(v=exchg.140).aspx for further information.

https://msdn.microsoft.com/en-us/library/office/jj900169(v=exchg.150).aspx
 

Resolution

Using the Autodiscover service to find the most appropriate URL for the specified user's mailbox instead of using a hard-coded EWS URL means that your workflow always uses the correct EWS URL for that particular mailbox. Autodiscover determines the best endpoint for a particular user (the endpoint that is closest to the user's Mailbox server).

You can also do a manual check on the pre-requisites for exchange integration to see if they have been met, references provided below.

http://help.k2.com/onlinehelp/k2blackpearl/icg/4.6.9/webframe.html_exchange_integration.html
http://help.k2.com/kb001189