In Exchange 2010, the following error logs quite often in the application log but no noticeable impact to users. The error in question:

Exchange 2010 – Event ID 108 Outlook Web App couldn’t connect Exchange Web Services due to a configuration error. Response code = “500”

The strange thing is, no follow up error is logged in Exchange regarding this. As a test, pointing to a test pool on the load balancer did not produce any errors on my outlook client, I was able to delete mails, reply to emails, close and open outlook and was constantly connected to Exchange throughout the whole testing process.

Disabled Add-ons within outlook and added them back and simply could not re-produce the error.

On the Exchange side, bindings were set correctly, ran the BPA in Exchange and no errors came back. This had me thinking that due to the large environment at hand, it could possibly be that the default settings in the Web.Config file needed to be looked at.

To get to this file you can navigate to the following directory:

  • C:\Microsoft\Exchange Server\V14\ClientAccess\exchweb\ews\

I first make a backup before modifying the file, once you have it open, locate the following entry, take note there is about 7 of them:

  • maxBufferSize=”81920″

Once located, increase the value and then save the file. If you take a look at the application log again in event viewer, you will notice 3 informational alerts logged.

After making the above change, the above error stopped logging.

This is for Exchange 2010 but I think that Microsoft should provide a bit more detail in the error for troubleshooting.

Hope it helps.