Gregadethhh

I installed disc 1 and 2, then tried to invite my girlfriend through the roster and it said I was "Not Joinable" so I went Infinity to play multiplayer and it would not connect to Halo 4 server yet all my Xbox Live friends are partied up playing Campaign/Slayer? I've tried EVERYTHING, re-installed both discs, restarted my xbox, restarted my router, deleted save file, cleared hard drive cache and the problem still persists is anyone else experencing these problems or know of any solutions? I can't even play system link