Firefox is only going to continue to raise its standards for secure connections going forward, so we need to know why it is objecting to the certificate or connection.

Does Firefox display an error code in the page? Sometimes this is in a section called Technical Details that you need to expand. Try to copy/paste as much of that as you can into a reply (you can partially XX out any sensitive information).

Attached is a Screenshot of one example MS Lync Meeting certificate from the Lync Server.

Thanks

When I the the top level https://meet.rtc.va.gov/ server I get a different certificate, but I suspect it has the same issue. On the Details tab, I see the hierarchy. The Federal Government's root signing certificate that vouched for the top certificate in the attached screen shot is not in Firefox's certificate store, so I get the unknown issuer error.

Judging by the number of alternative server names listed in the Subject Alt Name field (only half are shown in the screen shot), my guess is that you have to keep adding exceptions because each time you hit the service it can switch you to a different server. I don't think Firefox has a way to make a certificate exception for partial (wildcard) domains.