by 
Update []:
Looks like we've got a permanent fix! Halo's Brian Jarrard has confirmed that the issue should now be "resolved" across both Xbox consoles and the Xbox app for PC.
Original Story: Have you bought the Premium Edition or Premium Upgrade for Halo: Campaign Evolved, only to find it's not working properly? You're not alone - and Halo Support has now issued a statement about it.
In a nutshell, it seems most Premium owners were unable to get early access across Xbox Series X, Xbox Series S and the Xbox PC app when it began earlier today, and they're still being locked out at the time of writing.
Here's the statement:
It's been over an hour since the intended launch as we're highlighting this, so we assume it's not something that can just be fixed by pressing a button! Nevertheless, they'll undoubtedly be working on this as a matter of utmost priority.
We'll keep an eye on it and let you know when it's fixed, but in the meantime, just know that you're not alone in being unable to access the game right now. Hopefully we're just talking a few hours at most until it's resolved.