Halo Reach & CE won't be recognized as installed

I downloaded MCC for PC with Game pass, and for some reason it won’t let me play Reach or CE. The game starts up fine, but when I try to play it says im missing the DLC, even though I have the DLC installed. I’ve tried re-downloading it (around 4 times), and have tried restarting my PC. If anyone knows a fix, can you please tell me.