535-5.7.8: Username and password not accepted

GmailSMTPSign-in problem

The error usually looks like this:

535-5.7.8 Username and Password not accepted. For more information, go to https://support.google.com/mail/?p=BadCredentials

What it means

Google rejected the username and password your app sent.

Common causes

  • The password is wrong – or it is your main Google password, which can’t be used in email apps when 2-Step Verification is on.
  • For Google Workspace accounts, Google no longer allows sign-in with just a password (“less secure apps”) – OAuth 2.0 is required.

How to fix it

  1. Personal Gmail accounts: turn on 2-Step Verification and use an app password.
  2. Google Workspace accounts: use an app that supports OAuth 2.0, or Auth-Email to add OAuth to apps and devices that only support passwords.

Tools to help diagnose it

Email server checker

Check any IMAP, POP or SMTP server’s encryption, certificate and supported sign-in methods

SMTP connection tester

Spin up a real SMTP test server and diagnose your email sending configuration in real time

Can’t update your app to use OAuth?

Auth-Email fixes sign-in errors like this one without changing your app, printer, scanner or script. It signs in to Gmail with OAuth on your app’s behalf, while your app keeps using a normal username and password over IMAP, POP or SMTP.

Read the docsTry Auth-Email →

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