550 5.7.28: unsolicited mail from your IP, blocked
Gmail has blocked mail from your IP because of an unusual rate of unsolicited mail from it. It is the permanent counterpart of the 421 4.7.28 limits.
- Gmail
- Provider
- Permanent (5xx)
- Class
- Sources checked
- Author
At a glance
- Code
- 550 5.7.28
- 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 5.7.28 There is an unusual rate of unsolicited email originating from your IP address.
What it means
Gmail has seen an unusual rate of unsolicited mail from the IP and now blocks mail from it, instead of rate limiting it as the 421 4.7.28 replies do. Google links the reply to its sender guidelines. Messages are returned to you, and nothing from that IP will arrive until its standing with Gmail improves. Stop the mail that drew the complaints, check whether the IP sends anything you did not intend, and come back slowly, starting with your most engaged recipients.
Common causes
- High spam complaint rates on mail from the IP.
- Sending to purchased, scraped or stale lists.
- A compromised server or account on the IP sending spam.
How to fix it
- 01Stop sending to Gmail from the IP.
- 02Check IP reputation and spam rate in Postmaster Tools, and look for traffic you did not send.
- 03Clean your lists and remove the stream that draws complaints.
- 04Resume at low volume on a single connection and raise it gradually.
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 4.7.28Unsolicited mail from your IP, temporarily blocked.Gmail has temporarily stopped accepting mail from your IP, which goes further than a rate limit, because of the amount of unsolicited mail it has seen from it.
- 421 4.7.28Unusual rate of mail from your IP.Gmail is rate limiting mail from one of your sending IP addresses because the rate of mail it sees from that IP is unusual.
- 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.
- 5.7.28Mail flood detected.The receiving system thinks the message is part of a flood of similar abusive messages, such as one caused by forged web form signups, and deferred or rejected it.
Further reading
All 108 Gmail codesEvery code in the wikiPaste your own bounce