550 5.7.1: missing or invalid From header
Gmail rejected the message because it has no From header, or the From header does not contain a valid email address.
- 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 Messages missing a valid address in the From: header, or having no From: header…
What it means
RFC 5322 requires every message to have a From header with at least one valid address, and Google's sender guidelines require messages to follow RFC 5322. Gmail rejects messages that have no From header, or whose From holds no usable address. Google documents two wordings: one about a missing or invalid address in From, and one saying the message is not RFC 5322 compliant because the From header is missing. Both come from sending software, most often scripts and devices that build their messages by hand.
Common causes
- A script or device that sends without adding a From header.
- A From header holding only a display name, with no address.
- A malformed address in From, such as one missing the @ or the domain.
How to fix it
- 01Inspect the raw headers of a sent message.
- 02Add a From header with a complete address, for example From: Name <name@example.com>.
- 03Use a mail library that builds the header for you.
- 04Resend once the header is valid.
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
- 550 5.7.1More than one sender in From.Gmail rejected the message because its From header lists more than one address, or the message has more than one From header.
- 550 5.7.1Invalid domain in the From header.Gmail rejected the message because the domain in its From address is not written in a form that RFC 5322 allows.
- 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