If you're seeing different characters on Steam than what you should be, then you set up Cross-Save with a different Steam ID than the one you're using. The authentication error should be stating that you're trying to authenticate to an account that's different from the one you linked to Bungie.net. You linked and enabled Cross-Save with https://steamcommunity.com/profiles/76561198856666555 . You can use Steam's Forgot Password to figure out the login username for the account, and the password would be what you normally use since you authenticated to it for Cross-Save. You most likely signed in through an email instead of a username, and as such, logged into an old account you may have forgotten about. Unfortunately, since you completed the Cross-Save setup, you have two options: 1) You need to log in on the Steam client with the Steam ID you set up with Cross-Save in order to play using your characters on Steam as-is without making any further changes. 2) You'll need to disable Cross-Save, wait 90 days, then reenable Cross-Save with the correct Steam ID. After disabling Cross-Save, you can unlink the incorrect Steam ID in your Bungie.net settings then link the correct one. The 90-day wait must be waited out if you disable Cross-Save; it will not be reduced or removed. Those are the only two ways to access your Xbox characters on Steam.