*If there's a better group to post this to, please advise..The PlayOnPhone feature has stopped working for some reason. There's two error messages relevant to the condition, but in researching them both i don't believe any of the possible fixes apply to our enviroment..On the UM Server:The Unified Messaging server failed to exchange the required certificates with an IP gateway to enable Transport Layer Security (TLS) for an incoming call. Check that this is a configured TLS peer and that the correct certificates are being used. More information: A TLS failure occurred because the certificate that was presented by the remote server is not trusted. The error code was "-2146762487" and the message was "A certificate chain processed, but terminated in a root certificate which is not trusted by the trust provider". .On the CAS Server:The Unified Messaging Web service was unable to process a "PlayOnPhone" request for user "UserName". The error was "A valid Unified Messaging server could not be found for dial plan OCS.".All of certificates use FQDN's and are valid. The dial plan has valid UM servers associated with it. Intermediate certificates seem to be in order on both servers, i think.Any ideas?

i'm guessing then you've already looked at the followinghttp://www.microsoft.com/technet/support/ee/transform.aspx?ProdName=Exchange&ProdVer=8.0&EvtID=1113&EvtSrc=MSExchange+Unified+Messaging&LCID=1033are you using an internal ca? if yes, then do both servers trust the internal ca?

Yes, however i'm not sure what "the certificate presented by the IP/VoIP gateway" is referring to. I'm assuming this is the Cisco Call Manager? ..Or is it the physical IP gateway(router) the UM server connects to?

Hi,I recommend you to post the issue in OCS forum to get relevant help.Office Communications Server http://social.microsoft.com/forums/en-US/category/officecommunicationsserver/Thanks.Regards,Xiu

Hi Xiu. It's true that we're seeing this issue within our OCS dial plan, however we're also seeing it in dial that aren't connected to OCS or use any OCS components. That is, it's affecting everyone in the company, OCS or otherwise.