I have a user that cannot get their IM to work after having the pc re-imaged but can make phone calls/send emails via UPC. I tested through the VPN with my PC and it works fine. We are using CUCM 6.1.2, CUPS 7.0(1.13056) - I did create a report from their client and saw in the "resiplog.txt" file the error:
got a sip message: SIP/2.0 503 Service Unavailable.
Also this error in UnifiedClientLog4CXX.txt: CSuaCallControlManager.Singleton.Asynchronous::CProxyRegistrationHelper::onFailure - Failed to register! error-code: 503, msg: 'Service Unavailable'. Retry in 20 second(s).
The user was built the same as my client, not sure where to look other than re-installing the client and try again.
Thanks for any help.