I'm recently having 2 issues with Mumble:

1. Users that are not in the admin group no longer have a link to mumble and cannot connect
2. Some users can no longer connect to mumble using a pre-programmed favorite server in the actual mumble client. It says the certificate or password is invalid. I followed the instructions on how to resolve this from Mumble's website but it never works.

Anyone able to help?

Looks like you figured it out =)

You can also add the Mumble widget to your front page. It generates a connect link for users.