"Due to an expiring certificate no Mumble 1.2.2 or newer released before today (15.01.2012) will work on the Windows Platform after 15 January 2012 11:36:47 GMT. If such an outdated Mumble is launched after that date the error message "A referral was returned by the server” will be displayed by Windows and Mumble will not start."
So if you downloaded Mumble soon after we launched the new website, it will not work any longer. You will have to get the new Mumble 1.2.3a from THIS LINK or directly from the Mumble SourceForge page.
Once you get version 1.2.3a installed, you will again be able to log in via our website.
-Ati


