With the release of Ubuntu 12.04 I decided to upgrade the server running my mumble server and I wanted to use my new wildcard certificate so my mumble server would have a nice shiny green background. All went well with my upgrade to 12.04 and getting nginx to use my certificate was easy. Next was to add my certificate to mumble and then I ran into a problem. No matter what certificates I provided to the config (sslCert and sslCA) I would always get his error when a client tried to connect.
1 => <1:(-1)> New connection: XXX.XXX.XXX.XXX:XXXXX
1 => <1:(-1)> SSL Error: No certificates could be verified
1 => <1:(-1)> Connection closed: [-1]
Long story short: I added the ca-bundle.pem from StartSSL to /etc/ssl/certs and then it all worked.