There's actually two problems here with Uplay. Problem number 1 is that it's an old version of Uplay that needs to be updated to Ubisoft Connect. For those of you who are using two factor authentication, you will get a failure when attempting to login. This particular error will happen every single time. You have to disable two factor authentication - because this old version of Uplay does not support it. Once you disable 2FA on your Uplay account, you'll be able to login. Upon logging in, you'll get the same one time error everyone else is talking about here for this game. Try once more and this second error will not happen again. Uplay will then update itself to Ubisoft Connect, and will validate that you are the owner of Watch_Dogs and adds it to your Ubisoft Connect account. Once you get past this and are able to get to the title screen of the game, you can reenable two factor authentication again and you should no longer run into problems with Uplay after this.