when I try to watch it, the only option i have is to “Buy Halo”
no “Play” option.
when i press Buy Halo, it just launches the MCC. I have the Disc copy of the game. Whats going on here?
There should be a code that came in the box with your copy of MCC, you have to redeem that first in order to watch it. You may have to restart the Halo Channel after redeeming to watch it (or possibly the xbox).