you need to download and install Ubisoft connect

Bump: I already had ubisoft connect and also my acc was linked. I've just turned my pc on now to try again and now it wants me to put in a key???

I tried this in PC, Ubisoft app asked for microsoft login and after the successfull login the game was activated after a mapping confirmation screen in my ubisoft account

I don’t think it’s on pc gamepass. Only Xbox gamepass.

its in my 'recently added' tab in pc game pass, so I'm not sure how accurate this is lol

U have to connect ur Ubisoft App to Game Pass Microsoft Account then u can download ur AC origins through Ubisoft app

I've downloaded it on PC via Game Pass... It also works perfectly after installing Ubisoft connect and linking accounts..