Situation: The client use gmail on his Outlook. It doesn’t work since yesterday. It repeat for the password. He sue he enter the correct password. He can access mail on website.
Troubleshooting: 1. Google prevented a sign-in from a less secure app. You may need to turn on 2-Step Verification on gmail.
How to turn on 2-step Verification on Gmail
2. Sign-in attempt was blocked: Someone just used your password to try to sign in to your account from a non-Google app. Google blocked them, but you should check what happened. Review your account activity to make sure no one else has access. Login gmail website to take action.
3. Login gmail to generate an App Password.