Server Sight problem

I had this problem for while. Everytime I look at the master server, I see many server's running on the master server (Lets say 13 for example).
Then when I run Srb2 and click on "Join Game", There's only 2 or 3 server's there! Then I checked the master server again and there is still the same number of server's there 15 seconds ago. I tried and unblock my firewall and still I can't see the right amount of server's in the Srb2.exe then in the Master server.

Can Someone help me?

Maybe those are the only ones available in your region.

It only shows servers of the same version that you can actually join.