Ughhhh… This just started popping up after a whole weekend of play and some practice today…
“Your account is unauthorized to play Halo Infinite”
Having the same problem 
Access to the flight is completely down until Friday. Nothing unusual here.
<mark>This post has been edited by a moderator. Please do not purposely bypass the word filter.</mark>
*Original post. Click at your own discretion.
Today is Friday F#%K nuckle!
The “Not authorized” message that appears is because the flight is currently offline and not scheduled to start until sometime in the evening, west coast time [PST]. An exact time has not been released yet.
If you are still experiencing this issue after the flight goes live, check that you are on the correct account or your account isn’t logged in anywhere else.