Hmm.. I just installed version 1.2.17 from the https://mumble.info
site and it worked with the redirect address. The actual IP is 188.8.131.52 but is subject to change.
Make sure you have Mumble set to accept certificates and you can also maybe input your old certificate from
Make sure you are running it as administrator (right click/properties/compatibility/privilege level).
Is there any error message or anything else you can tell me?