554 5.7.1 Message rejected as spam Email / SMTP Origin: Network Last updated 4 Nov 2026

SMTP: 554 5.7.1 Message content rejected / Your message looks like spam (spam score exceeded)

The receiver's content filter scored your message as spam based on its text, links, headers or sender reputation and rejected it during delivery.

Exact message you may see 554 5.7.1 Message rejected as spam554 5.7.1 Message content rejectedMessage looks like spamspam score exceeded threshold550 5.7.1 Our system has detected that this message is likely unsolicited mail
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Seen on: SMTP

Meaning

Spam filters weigh many signals: missing authentication, all-image mail, URL shorteners, deceptive links, spam trigger words, bad HTML, mismatched From/Reply-To, new domains and low reputation. Authenticate (SPF/DKIM/DMARC), send plain-text alternative, use your own domain links and ask the recipient admin to allow-list you if you are legitimate.

Common causes

  • Poor sender reputation or new domain
  • Missing or failing SPF/DKIM/DMARC
  • Suspicious links, URL shorteners or mismatched hrefs
  • Image-only message or broken HTML
  • Content resembling known spam patterns

⚡ Quick fix

  1. Fix authentication first, then content
  2. Check the message with mail-tester.com
  3. Ask the recipient's admin to review the rejection ID in the bounce

Detailed fix by platform

Linux

  1. spamassassin -t < message.eml | tail -40 lists the rules that triggered on your message

How to diagnose

  1. Auth — SPF/DKIM/DMARC pass?
  2. Content — Links, HTML and tone?
  3. Reputation — Domain/IP age and history?

🔧 Still not fixed?

Many errors look alike. If the steps above didn’t solve it, one of these is probably what you’re facing:

Where this error sits

Origin: Network. Errors that are often confused with or caused by this one (click to open):

421 4.7.0 Try again later (rate limited) — SMTP: 421 4.7.0 Our system has detected an unusual rate of unsolicited mail originating from your IP address. Mail sent from your IP address has been temporarily rate limited (Email / SMTP)421 4.7.0 Try again l…450 4.7.1 Greylisted, please try again later — SMTP: 450 4.7.1 <user@example.com>: Recipient address rejected: Greylisted, see http://postgrey.schweikert.ch/help/example.com.html (Email / SMTP)450 4.7.1 Greylisted,…451 4.3.0 Local error in processing — SMTP: 451 4.3.0 Error: queue file write error / 451 Requested action aborted: local error in processing (Email / SMTP)451 4.3.0 Local error…452 4.2.2 Mailbox full / over quota — SMTP: 452 4.2.2 The email account that you tried to reach is over quota (Email / SMTP)452 4.2.2 Mailbox ful…550 5.7.1 Blocked using zen.spamhaus.org — SMTP: 550 5.7.1 Service unavailable; Client host [203.0.113.5] blocked using zen.spamhaus.org (Email / SMTP)550 5.7.1 Blocked usi…550 5.7.26 — 550 5.7.26 This mail has been blocked because the sender is unauthenticated (SPF/DKIM/DMARC) (Email / SMTP)550 5.7.26DMARC fail: SPF and DKIM not aligned — DMARC: dmarc=fail (p=REJECT) — SPF and DKIM pass but domains are not aligned with the From header (Email / SMTP)DMARC fail: SPF and D…554 5.7.1…

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