Try this:
Alright, so the problem was from the ISP, they have the ports for mumble blocked for some reason.
Here's how you can bypass it:
Open the BF2

R launcher> Open the options> PR Mumble> launch> Configure> Settings> Network
at the proxy options in the same page, change the proxy type to HTTP(S) proxy and use this host name and port:
195.229.241.174
8080
You don't need to set a username or password. But if you have any other proxy server you want to use, I guess that will work too but this is the one that I'm currently using and has been working so far.