CRM Emails to Exchange EWS Directory Fails via the LoadMaster
This article covers how to resolve the issue when CRM emails to Microsoft Exchange EWS fail via the LoadMaster.
The customer was facing an issue where emails sent from the CRM application server to the Microsoft Exchange EWS would fail when the request was via the LoadMaster but it would work when bypassing the LoadMaster.
|Steps to Reproduce:|
|Error Message:||"The underlying connection was closed: An unexpected error occurred on a send". Note: This message was seen on the CRM application logs.|
|Cause:||The Microsoft EWS directory requires to see the client's IP address.|
The Virtual Service (VS) in this case need to be a transparent passthrough service. Transparent means the LoadMaster will use the client IP address when forwarding the request to the real server (RS). Passthrough means that the SSL/TLS traffic should not be offloaded on the LoadMaster and should be handled by the RS (see screenshot).
For more information on how to configure a transparent VS and the requirements that must be met in order for the set-up to work, please review this article Transparency.
Nevertheless, sometimes transparency may not be possible for the customer environment due to the requirements that must be met. In this case, the customer could opt for Direct Server Return (DSR) instead. For more information on how to configure DSR, please review this article Configuring DSR.