Hi,

I'm new to all this. Can someone please help. We are on a domain and recently our Certificate for Lync expired, so now "Lync" is not functioning. We also have an edge server. I know it has expired because I see it in the event viewer. So the first question, How do I renew the certificate for Lync, I can't find it on the server. Once I get that information, Do I install the certificate on the Lync server or the Edge server? thank you for helping a newbie!

Both of those servers (front end and edge) need certificates, you might also want to check for a certificate on a reverse proxy as well (if you ping meet.yoursipdomain.com externally, whatever server that IP NATs to).  You request them using the deployment wizard, clicking "Install or Update Lync Server System" then re-running step 3.  Once you have your certificate assigned, you'd need to restart services.  Here's a link that walks through it: http://uclobby.com/2013/09/16/renewing-lync-server-20102013-certificates/