534 5.7.9: Application-specific password required (Gmail)
Your Google Account has 2-Step Verification on, so Gmail wants an app password from this app, not your normal password.
Sign-in problem Your app or device couldn't sign in to your own mail server, so the message was never sent. Fix the sign-in settings.
What the bounce message looks like
The wording changes from one provider to another. These are typical examples:
534-5.7.9 Application-specific password required. For more information, go to https://support.google.com/mail/?p=InvalidSecondFactorCommon causes
- The app is using your Google password
- The app doesn't support "Sign in with Google"
How to fix it if you sent the email
- Create an app password at myaccount.google.com/apppasswords (2-Step Verification must be on) and paste it into the app's password field.
- Or use an app that supports "Sign in with Google".
If you manage the receiving or sending mail system
- If app passwords are turned off for your organization, use the Google Workspace SMTP relay for devices.
Free tool: paste the full bounce into the bounce message decoder to get a plain-English reading of every code in it.
Questions people ask
- What does 534 5.7.9 mean?
- Your Google Account has 2-Step Verification on, so Gmail wants an app password from this app, not your normal password.
- Is 534 5.7.9 a hard or soft bounce?
- Sign-in problem. Your app or device couldn't sign in to your own mail server, so the message was never sent. Fix the sign-in settings.
- Should I remove the address after a 5.7.9 bounce?
- No. The message never left your own mail server. Fix the sign-in or sender settings and send again.