550 5.7.1: more 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.
- 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 with multiple addresses in the From: header are not accepted.
What it means
Gmail accepts one author address per message. Google documents two cases: several addresses in a single From header, and a message with more than one From header, which RFC 5322 does not allow at all. RFC 5322 does permit several authors in one From when a Sender header names one of them, but Gmail refuses those as well. More than one From header is also a known way to confuse which sender a reader sees. The fix is in the sending software: one From header with one address.
Common causes
- Software that puts a list of addresses into From.
- A template or gateway that adds a second From header.
- A message built by joining headers from two sources.
How to fix it
- 01Inspect the raw headers of a sent message.
- 02Keep a single From header with one address, and put other people in Reply-To or Cc.
- 03Fix the template or gateway step that adds a second From.
- 04Resend once only one From remains.
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 5.7.1Missing 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.
- 550 5.7.1Duplicate headers.Gmail rejected the message because a header that may appear only once, such as Subject or Date, appears more than once.
- 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