Follow my steps!!!
- Go here: C:\Program Files (x86)\Steam\SteamApps\common\Call of Duty Ghosts
- Now find the file named iw6mp64_ship.exe
- Right click on iw6mp64_ship.exe and Run it as administrator
- Try to go online now (you might have to wait 10 or 20 secconds)
this worked for me, I really hope it also does for you!
Goodluck