Blank screen running vix means you are not connected to your server.
Press OK twice and you should see your server details on the left hand side.
(which you won't if you have a blank screen)
If you are running mg cam 1.38 try 1.35a
Change the cam, reboot the router, stop and start the cam again and see if the channels clear.
Sometimes 1.38 is a bit dodgy.
Still no joy try using CCcam.
Bit of a weird one, but my living room box works fine using 1.38 but my bedroom box will only clear using CCcam ??
Even if I switch the boxes over it's still the same, thought it might be something to do with running room.
Still no joy check with your server if everything is alright at their end.