I am unable to sign in via apple to You Tube after explicitly following Google/YouTube instructions to the letter. I still get an error saying “Authentication Failed”. If any one has idea about this solution please help me out.
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Did you change your “Google password” somewhere else, like maybe on your phone?
I ran into that same problem sometime ago when I set up Gmail on the phone. I didn’t realise that the Gmail password became my Youtube password.
Somehow or the other I wound up with a Google Plus account too, and I have no idea how.