Halo 5 Guardians Error Authorising User

I have not been able to play online because of how I constantly get this message for now 4 days straight.
Halo 5 says that I am unable to play online even though I have xbox live for two weeks, I’ve only started yesterday. After that it says that there is a profile sync error.
Could 343 please fix this already, I have seen people having the exact same situation since the game had released.

Have you tried a hard reset of your Xbox or restarting your internet router? Those options might work.