I've been using Google services (Search, Gmail, and Messages for Web since the browser became available on the Model 3 with no real issues. I just changed my Google password after using the same one for far too long and when I tried to login with the new password I got an error message saying the browser is not allowed due to security. (Sorry for the crappy picture) After trying both the Browser and the Youtube app with the same result. After testing if maybe it was two-factor authentification, It was not. I tried logging into a non-Google website (such as https://teslaownersonline.com/ ) using the use Google credentials option. It does not need to be a successful login. After that, I went to the YouTube app and the login process worked normally.