We have setup communication between Ops Mgr 2012 SP1 and untrusted Lync servers using certificates. Communication was working for 3 days, monitoring and alerting, then the untrusted servers went grey in Opsmgr console. Receiving EventID 21010 in Opsmgr event log. For setup, we followed the steps in the blog called step-by-step-for-using-certificates-to-communicate-between-agents-and-the-opsmgr-2007-servers and port 5723 open both ways.
We are very new to SCOM and monitoring untrusted. Would appreciate any help or insight as to why we lost connections. No environment changes were made that would have caused the loss of communication.