On 1st of January 2014 at 00:00 CET FrozenSand did shut down the 4.1 master
servers. So, if you still play 4.1.X and want to see online servers playing urbanterror 4.1, you should change the master browser string.Open the console and write:
\cl_master master.quake3arena.com
And to check you did it properly, write and press intro or tab:
\cl_master
If that doesn't work put this line in your hosts file.
192.246.40.56 master.urbanterror.net
Linux file location is /etc/hosts
Windows file location is c:\windows\system32\drivers\etc\hosts