This article covers methods to resolve PHPMailer SMTP error password command failed.
To fix this SMTP issue, you need to:
1) Login to your Gmail account using the web browser.
2) Click on this link to enable applications to access your account: https://accounts.google.com/b/0/DisplayUnlockCaptcha
3) Click on Continue button to complete the step.
4) Now try again to send the email from your PHP script. It should work.