Found a good solution today if you’re receiving the following error:
SMTP -> ERROR:Password not accepted from server. Code: 535 Reply: 535-5.7.1 Please log in with your web browser and then try again.
Even if the Gmail account credentials are correct, Google’s servers may still block the server attempting to authenticate (more than likely due to a new server location and/or recent password change).
To get around this, make sure you are logged in using the same Gmail account in your browser, and then simply open the link below and step through the process of verification: