5.7.22No valid author-matched DKIM signature found

The receiving system permanently rejected the message: at least one DKIM signature passed verification, but none had an identifier matching an author address in the From field. Do not retry the same unchanged attempt.

The standard X.7.22 pattern is returned when a message contains at least one passing DKIM signature, but no passing DKIM signature has an identifier that matches any author address found in the From header field. This is a special case of X.7.21 and violates the advice in Section 6.1 of RFC 6376. Code 5.7.22 applies this detail in the permanent-failure class.

The leading digit 5 denotes a permanent failure of the current attempt. The code confirms that at least one DKIM signature passed verification; the problem is that its identifier does not match an author in the From field, not that every DKIM signature is invalid. The code alone does not identify the layer where the mismatch arose.

Class

Permanent failure

Retry

Do not retry unchanged

Suppression

Check the full context

Operational guidance: stop automatic and manual retries of the same unchanged attempt because they will not change the match between the DKIM identity and the author. Consider a new, controlled attempt only after a confirmed correction and verification that at least one DKIM signature both passes and is author-matched; check suppression again first.

Operational guidance: do not automatically suppress the recipient address or domain based on 5.7.22 alone. Inspect the complete response, From field, DKIM results, configuration of the systems involved, and event history, then make the suppression decision according to the confirmed cause and applicable policy.

• The message contained at least one passing DKIM signature, but no passing DKIM signature had an identifier matching any author address in the From field.

1. Inspect the raw SMTP response or nondelivery report and confirm the exact 5.7.22 code and a basic reply in the 5xx class; retain the complete response text.
2. Correlate the response with the intended message, attempt time and stage, and system that returned the code. In the message copy from the evaluation point, inspect the From field, DKIM-Signature headers, and available verification results or logs, and confirm that at least one signature passed.
3. Compare the identifiers of every passing signature with the author address or addresses in the From field. Inspect signing, transport, and verification logs and configuration to establish where the mismatch arose, without assigning responsibility from the code alone.
4. Stop unchanged retries. After a confirmed correction, demonstrate that at least one DKIM signature passes and is author-matched, check suppression again, and make one controlled attempt.

Compare 2.7.0 and 4.7.0 for other or undefined security statuses in the success and temporary-failure classes, respectively, 4.7.1 for a temporary refusal of unauthorized delivery, and 4.7.12 for a required authentication-mechanism transition. None denotes a permanent rejection because no passing DKIM signature was author-matched.

• 2.7.0Other or undefined security status (success)
• 4.7.0Other or undefined temporary security status
• 4.7.1Delivery not authorized, message temporarily refused
• 4.7.12Authentication mechanism transition required

The canonical Tier-0 meaning of X.7.22, its relationship to X.7.21, its reference to the advice in Section 6.1 of RFC 6376, and its class-5 application were verified against the IANA registry and RFC 2034, RFC 5248, RFC 6376, and RFC 7372 as of July 17, 2026. Diagnostic, remediation, retry, and suppression recommendations are separate operational guidance; this record contains no provider-specific practice.

• iana-smtp-enhanced-status-codesT0 source

  Enumerated Status Codes / X.7.22

• rfc5248T0 source

  Section 2.1: registry fields and non-exclusive Associated Basic Status Code

• rfc2034T0 source

  Section 4: enhanced status class agrees with SMTP reply class

• rfc7372T0 source

  IANA registry reference for X.7.22

• rfc6376T0 source

  IANA registry reference for X.7.22

Last verified: 17 July 2026