Postman SMTP on "[Plugin: WP Mail SMTP] Test Message Sent The result was: bool(false)"

Ok. @Bru17:

1. You have to change your password. It's included in the output you posted, and someone may try to pillage your google account
2. The error is : ERROR: Password command failed: 535 5.7.8 Error: authentication failed: authentication failure, which means Gmail is no longer accepting this password for sending mail. Are you sure your password is correct?

If you're sure your password was correct, then you've run into this problem and you have two solutions:

• Use OAuth 2.0 authentication instead of password authentication or
• Enable less-secure apps in your Google account