Hey PblLb, welcome to the forums - sorry to read you're having this authentication error, but I'll be happy to advise you.
Normally, this happens when you launch a game on Steam or Epic, and attach it to a Ubisoft Connect account, but then on subsequent plays you log into a different Ubisoft Connect account.
So, do you recall having any other Ubisoft Connect accounts? If so, please start up Ubisoft Connect, click your account username at the top-right, choose log out, and then log into the other Ubisoft Connect account. Then try once more to start up the game via your launcher.
If that doesn't work, or if you have trouble finding the correct account, please get in touch with us via one of these channels:
Support website
Facebook PM
Twitter DM
Let me know if I can clarify these instructions at all![]()