I can't access the Ghosts servers for Xbox One either. Yes the Xbox Live service status shows limited website services but not the Xbox Live Core services. This seems to be an Activision server problem. My internet works fine, speediest.net shows plenty of speed (Speedtest.net by Ookla - My Results). And yes I can stream video, play Assassins Creed online, download Madden and play online as well, but I can't play Ghosts online.
I'm just glad I didn't spend the money on the Season Pass just to get new maps and now can't play online.