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On Premises Exchange - The EWS URL could not be validated.

This article was created in response to a support issue logged with K2. The content may include typographical errors and may be revised at any time without notice. This article is not considered official documentation for K2 software and is provided "as is" with no warranties.


When trying to send any emails in a Smartform or workflow, there is a hostserver error and no email is sent. The error is: "The EWS URL could not be validated." This issue only occurs in On Premises Exchange Servers.


No Emails are sent out and we get errors in the Host Server logs about the URL not being validated.

Make sure you can browse to the EWS Autodiscover URL on the K2 Server.

Also make sure that all of your K2 Service Account permissions are setup correctly in Exchange. The Connection String editor.

If the User Login is pointing to a UPN like Bob@denallix.com, the Email functionality will not work.

This is because K2 must have the login in FQN/UPN (DENALLIX\Bob) to be correct.


Change the User Login in the Connection String Editor to be correct format FQN/UPN and restart the K2 Service to resolve the issue.