GameRanger and MekMatch are the browser that we use for casual activity or scheduled matches . For casual activity we prefer connect to MWMEL = MultiFormat server and for scheduled matches we connect to MWMEL = CCFC server . 
If you want connect to our servers need have your firewall configured and allow to your MechWarrior 4 Mercenaries the access to internet . If you do not know how to configure your firewall you should see carefully the step 22 of the section "INSTALLATION" of this blog . In order to work well the MekMatch and GameRanger and the Game Lobby of your MechWarrior 4 Mercenaries is also necessary to have open the UDP port 16000 , UDP port 2300 to 2400 , TCP port 2300 to 2400 and TCP 47624 from your router . If you not have these ports open and not know how open them you should also see carefully the steps 23 , 24b and 24c of the section  "INSTALLATION" of this blog .