Gmail and Google Workspace · permanent error
550 5.7.1: blocked for low IP reputation
Gmail permanently rejected the message because the IP it came from has a very low reputation with Gmail.
- Gmail
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550 5.7.1
- 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
550 5.7.1 This message is likely suspicious due to the very low reputation of the sending IP…
What it means
This is the permanent form of the IP reputation block. Gmail's view of the sending IP is poor enough that it rejects the message outright. Google's sender guidelines describe a related 550 5.7.1 case, in which the sending server's IP is on an IP suspended list, and say it can happen when you send from a shared IP with a poor reputation. On a shared IP the problem may be other senders; on a dedicated IP it is the mail you have sent. Either way, reputation recovers only after a stretch of better mail.
Common causes
- Recipients have reported mail from this IP as spam.
- Sending to old, purchased or scraped lists.
- A shared IP whose other senders send unwanted mail.
- A compromised server or account on the IP sending spam.
How to fix it
- 01Check IP reputation and spam rate in Google Postmaster Tools.
- 02Stop the stream that draws complaints, and send only to recipients who want your mail.
- 03If you are on a shared IP, ask your provider to move you to a better pool or a dedicated IP.
- 04Check the IP against public blocklists, and look for traffic you did not send.
- 05Resume slowly once reputation improves.
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
- Email sender guidelines (Gmail Help)support.google.com
Related codes
- 421 4.7.0Low IP reputation, rate limited.Gmail is rate limiting mail from your sending IP because that IP has a very low reputation with Gmail.
- 550 5.7.1Blocked for low domain reputation.Gmail permanently rejected the message because the domain it comes from has a very low reputation with Gmail.
- 550Mailbox unavailable.The receiving server permanently refused the message for this recipient: the mailbox does not exist, cannot be reached, or the server rejected the message by policy.
- 5.7.1Delivery not authorised.The receiving server refuses the message because this sender is not allowed to send to this recipient, as a result of filtering by host or by recipient.
5.7.1 at other providers
- 550 5.7.1Not authorized to send to this recipient.You do not have permission to send to this recipient, typically a group restricted to certain senders or a recipient protected by a mail flow rule.
- 550 5.7.1Public folder does not accept external mail.An external sender wrote to a mail-enabled public folder in Microsoft 365, which by default accepts mail only from authenticated senders.
- 550 5.7.1Sending IP blocked by Proofpoint Dynamic Reputation.Proofpoint’s IP reputation system has your sending IP on its block list because it has seen spam or viruses from it, so Proofpoint customers refuse your mail.
- 550 5.7.1SPF check failed.The recipient’s Cisco Secure Email gateway checked SPF, found your server not authorised for the sender domain, and its policy rejects that result.
- 550 5.7.1Rejected under your domain’s DMARC policy.Your message failed DMARC, your domain’s DMARC record asks receivers to reject such mail, and the recipient’s Cisco gateway did so.
- 550 5.7.1DMARC verification failed permanently.The Cisco gateway hit a permanent failure while verifying DMARC for your message, and the recipient’s policy rejects such mail. Cisco does not say what produces that failure.
Further reading
All 108 Gmail codesEvery code in the wikiPaste your own bounce