How do I fix "A referral was returned from the server." error?

This is caused by the internal certificate inside the mumble client expiring.

You can read details here:

The easiest way to fix it is:

  1. UNINSTALL your current mumble client.
  2. Download the latest version of the mumble client for windows from
  3. Install the new client.

Please open a support ticket if you have further issues.