An odd error creeped up in our Lync installation after installing the CU5 update available here: http://www.microsoft.com/download/en/details.aspx?id=11551
After installing the update mobile Lync Mobile stopped working, the diagnostic logging from a Windows Phone device showed an 500 error from the mcxservice..
Error : 374409110 : HttpRequestPump : Got a failure response to request MEXhttps://lyncext.contoso.com/Mcx/McxService.svc. Status: UnknownError. Code: 500.
A quick Google search didnt turn up any useful information, most errors related to the mobility service are regarding TMG config and certificates. Tested the mobilityservice from PS with “Test-CsMcxP2PIM” which completed succesfully. Started the logging tool and activated logging of the mcx service. Here I got the first clue, an error message complaining about the web.config file.
When I tried browsing to the external mcxservice from an external computer on https://lyncext.contoso.com/mcx/mcxservice.svc i got an 500 error, tried to browse to https://lyncfe.contoso.com:4443/mcx/mcxservice.svc from an internal computer and got the same error. Conclusion, the error was not caused by a TMG or FW issue since it also occured when browsing directly to the service from an internal computer.
I then tried to browse to the internal mcxservice on https://lyncfe.contoso.com/mcx/mcxservice.svc which returned the page correctly, but I noticed the header stated “McxService2 Service”. Compared this with an installation which didnt have the CU5 update applied to it and the service returned “McxService Service” without the 2…
I then searched through the web.config files and found that the web.config file for the external service had this line:
<service name=”Microsoft.Rtc.Mcx.McxService” behaviorConfiguration=”McxServiceBehaviorConfiguration” />
Compared to the web.config for the internal service which had this:
<service name=”Microsoft.Rtc.Mcx.McxService2″ behaviorConfiguration=”McxServiceBehaviorConfiguration” />
Changed the line in the external web.config file to say “Microsoft.Rtc.Mcx.McxService2” with the 2 and rebooted my phone, instant success.
Why the web.config file for the external site hadnt been updated I dont know, must have been locked in one way or another. Have not found anyone else that have had this issue so it’s probably not a common error.
Anyway, hope this can help if someone else encounters this problem.