Guides › 550 5.7.1 relaying denied
550 5.7.1 relaying denied: what it means and how to fix it
"550 5.7.1 Relaying denied" or "Relay access denied" means a mail server refused to pass your message on, because it doesn't know you're allowed to send through it. It's almost always a settings problem, not spam.
Rather not do this yourself? We find and fix what's sending your email to spam for $199. If there's nothing to fix, you don't pay.
What "relaying" means
A mail server accepts mail in two cases: for its own mailboxes, or from its own authenticated users who are sending somewhere else. Passing your message on to someone else's mailbox is called relaying, and servers only do it for users who have signed in. Otherwise anyone could use them to send spam. So when a server says relaying denied, it's saying: this isn't for one of my mailboxes, and you haven't signed in.
The usual causes
1. SMTP authentication is off
The most common cause. An email app, website or device is set to send through your provider's server without a username and password. Turn on SMTP authentication ("My outgoing server requires authentication") and use the full email address and password of a real mailbox. With two-factor sign-in, you may need an app password.
2. Wrong server or port
Sending on port 25 to a provider's incoming server instead of its submission server is a classic way to get relaying denied. For sending, use your provider's SMTP server on port 587 with STARTTLS, or 465 with SSL/TLS, as your provider documents.
3. A printer or scanner using scan-to-email
Office printers often send scans through an old SMTP setting that no longer works, or one that never authenticated. Update the printer's SMTP settings with the server, port and a mailbox login. For Microsoft 365 and Google Workspace, check their admin documentation for device sending: both have specific options for printers and apps, some of which need an admin to allow them.
4. A website or app sending through your mail server
A website form or plugin sending through your provider's server with no login, or with a password that changed, gets the same error. Update its SMTP settings, or use a proper SMTP plugin. See our contact form guide.
5. Sending from an address the account doesn't own
Some providers return 5.7.1 when you sign in as one mailbox but send from a different address. Send from the address you signed in with, or give that account permission to send as the other address.
6. On your own server: the domain isn't configured
If you run the receiving server, it may not know it's responsible for the recipient's domain. In Postfix, the domain needs to be a local or virtual destination or listed in relay_domains. In Exchange, it must be an accepted domain. If you're relaying out through another provider, check the relay login (in Postfix, the SASL password file and postmap).
Other kinds of 550 5.7.1
5.7.1 is a general "refused for policy reasons" code, so the same number appears with other messages. If the bounce mentions spam, a blocklist, DMARC or your IP, it isn't a relaying problem: see blacklist removal or check your domain with the free check. Always read the text after the code.
Want someone to sort it out?
We fix sending for your mailboxes, website, printers and apps, set up SPF, DKIM and DMARC, and test real emails to Gmail, Outlook and Yahoo. $199, and if there's nothing to fix, you don't pay.
Questions
What does 550 5.7.1 relaying denied mean?
The mail server refused to pass your message on to another domain because it doesn't recognise you as an authorised, signed-in user. It's usually caused by SMTP authentication being off, the wrong server or port, or a device or website using old settings.
How do I fix relay access denied?
Turn on SMTP authentication with a real mailbox's address and password (or an app password), and send through your provider's SMTP server on port 587 or 465. On your own server, make sure the recipient domain is configured as local or a relay domain.
Why does my printer get 550 5.7.1 when scanning to email?
Its SMTP settings are usually outdated or don't sign in. Update the server, port and login, and check your email provider's admin documentation for how printers and devices are allowed to send.
Is 550 5.7.1 always a relaying problem?
No. 5.7.1 means a policy refusal, and the text after it says which. Mentions of spam, a blocklist, DMARC or your IP point to a reputation or authentication problem instead.
Related: email blacklist removal · contact form emails going to spam · Microsoft 365 emails going to spam.