535 5.7.8: username and password not accepted
Google rejected the user name and password your client used to sign in to its SMTP server, so it will not send mail for it.
- Gmail
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 535 5.7.8
- Provider
- Gmail and Google Workspace
- Temporary or permanent
- PermanentRefused for good: the message comes back to the sender, and resending it gets the same answer.
- Who has to act
- The sender. The fix is on the sending side: your domain, your server or your list.
- What the server says
535 5.7.8 Username and Password not accepted.
What it means
This is Gmail's answer to failed SMTP authentication. Either the credentials are wrong, or they are the account's normal password in an app where Google requires something else: Google no longer accepts plain passwords from most third-party apps, which need an app password (available with 2-Step Verification) or OAuth sign-in. Google's current table prints this code as 5.7.80; the June 2025 version read 5.7.8, the code this entry uses and the one IANA registers for invalid authentication credentials.
Common causes
- A wrong user name or password, or an outdated one.
- The account's normal password used in an app, where Google requires an app password or OAuth.
- An app password that was revoked, or created for another account.
How to fix it
- 01Check that the user name is the full email address, and enter the password again.
- 02Turn on 2-Step Verification and create an app password for the client, or switch it to OAuth sign-in.
- 03Sign in to the account in a browser to clear any security block.
- 04For devices that can do neither, use the Workspace SMTP relay with IP-based authentication.
Sources
What this page rests on, checked on 20 Oct 2026. The explanation is ours; the reply text is the server's.
- Gmail SMTP errors and codes (Google Workspace Admin Help)knowledge.workspace.google.com
- Gmail SMTP errors and codes, version of June 2025 (Internet Archive copy)web.archive.org
Related codes
- 534 5.7.9App password required.The account uses 2-Step Verification, so Google will not accept its normal password from your mail client and asks for an app password instead.
- 534 5.7.14Sign in through a web browser first.Google refused your client's SMTP sign-in and wants the account owner to sign in through a web browser before the client tries again.
- 535Authentication credentials invalid.The server rejected the login because the username, password or token is wrong or not sufficient for this account, so no mail is sent.
- 535 5.7.8Login failed: invalid credentials.The SMTP server rejected the login because the username, password or token was wrong or not sufficient, so it will not accept mail from this session.
5.7.8 at other providers
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