Running Exchange 2010 SP1 Rollup 2. We have a test environment where this works and a production environment where for some reason it doesn't! This happens to internal clients. In Outlook 2010 if you try to set an out of office reply you receive an error "Your automatic reply settings cannot be displayed because the server is unavailable". I can set OWA out of office replies if I use OWA externally. Also mailtips show as "Mailtips could not be retrieved" in Outlook 2010 internally. In the event log on the CAS server you see: The service '/EWS/exchange.asmx' cannot be activated due to an exception during compilation. The exception message is: A binding instance has already been associated to listen URI 'http://servername/EWS/Exchange.asmx'. If two endpoints want to share the same ListenUri, they must also share the same binding object instance. I have so far performed the following: Checked IIS default site bindings and cannot see any host names specified Checked the web.config file under the EWS directory in Exchange and it doesn't specify any hostnames either I was away for two weeks and other work has been performed on the web.config file as another engineer removed the "require SSL" option from IIS and tried to edit out settings for HTTPS in the web.config file to offload SSL to a netscaler box. I have undone anything he reckons he did and replaced the web.config file with the one from our test environment but still have the same error. How can this be troubleshooted further? I do not know if this worked before I went away as I had just finished installing a default 2010 install into production (under co-existence so everyone is still on 2003) so the web.config and HTTP offloading may be a red herring, but it works in Test and so I cannot see why Production is so different? What information would people need to help out further? I have run the "Get-Outlookwebservices" and see the following: RunspaceId : 67bc1a62-ea7e-4a94-86a9-ae5e0862241d Id : 1113 Type : Error Message : When contacting https://servername/ews/exchange.asmx received the error Client found response content type of ' ', but expected 'text/xml'. The request failed with an empty response. RunspaceId : 67bc1a62-ea7e-4a94-86a9-ae5e0862241d Id : 1125 Type : Error Message : [Server] Error contacting the AS service at https://servername/ews/exchange.asmx. Elapsed time was 109 milliseconds.

Does anyone have any ideas now the weekend has passed?

Didn't have time to do anymore troubleshooting so have restored the CAS box using the recoverserver switch and set it up again which fixed the issue. The issue regarding mailtips and OOF not working was still present, but this time there were no event log entries on the server which was good. The mailtips/OOF issue happens because if you try to open a mailbox which is DIFFERENT to your currently logged on user (I was using the credentials of a 2010 user when it prompted me) then for whatever reason the OOF and Mailtips within Outlook resort to using your logged on user account. Using the "Run as" option when running Outlook 2010 solved the OOF and Mailtips not working after the restore was completed. God knows what changes were made to the web.config file but thankfully recoving servers in 2010 is simple enough!