Bounce with 5.7.1: 'message rejected' or 'not authorised'
5.7.1 means the receiving server is refusing your message on policy grounds, usually SPF/DKIM/DMARC or reputation.
Try this first
- 1Read the full reject text in the NDR, the reason is often inline
- 2Check SPF/DKIM/DMARC for the sending domain
- 3Check whether your IP is on a blocklist (mxtoolbox)
- 4For Microsoft recipients: check sender reputation in SNDS
When to bring us in
Some 5.7.1 codes come from transport rules on the receiver side, only they can fix those.
See also
- Our emails land in spam for some recipientsAlmost always an SPF, DKIM, or DMARC setting that is wrong or missing, or a sender name that mimics a well-known brand.
- Someone reports receiving phishing emails "from us"Read: spoofing. Someone is abusing your sender name, not necessarily your actual mailbox.
- An email bounces (NDR): delivery failedThe NDR text usually states the exact reason. Reading it is step one.
None of the above fits?
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