I recently had a security attack on my Google account and ended up changing my password. Now, ever since, Pokemon Go fails to authenticate. I have tried numerous suggestions found here and elsewhere with no luck. I have tried uninstalling and reinstalling, but still have had no luck. What can I do? Whenever I log in with my Google account, I fail authentication, but I can log in just fine with other accounts that I have not changed passwords for.
If a 3rd party authenticated service fails after a password change, it usually is because they're not aware you changed your password on the 3rd party. Try logging in with your old Google password. If you get in, fully sign out and back in again. If you fail to get in with your old, try your new password again.