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Yahoo and AOL temporary delivery error

Yahoo: Message temporarily deferred (TS* errors)

Yahoo temporarily delayed the message. Common causes include complaints, spam-like content, poor IP reputation, or unusual traffic.

Problem description

The Yahoo response contains:

Message temporarily deferred
Is this temporary or permanent?

Yahoo treats 421 and 451 responses as temporary. Let the mail server retry with backoff while you investigate.

Find the affected sending stream

  1. Save the complete response, Yahoo tag, sending IP, recipient, and timestamp.
  2. Let the mail server retry with increasing delay.
  3. Check for a sudden rise in volume, connections, invalid recipients, or complaints.
  4. Check the outbound queue for a compromised account, form, or server.
  5. Review the content and links sent by the affected IP or domain.
  6. If the same response continues, send Yahoo Sender Support a small set of exact log examples.

A DNS or authentication check can confirm general sender compliance, but it cannot prove why Yahoo issued this broad temporary response.

Frequently asked questions

Should Yahoo temporary deferrals be retried?

Yes. Let the sending server retry 421 and 451 responses with backoff. Do not create parallel retry storms.

Does a TS error prove that DNS is wrong?

No. Yahoo lists complaints, content, IP reputation, traffic patterns, temporary DNS availability, and temporary authentication errors as possible causes.

Related email diagnostics

Yahoo delivery errorsUnderstand Yahoo and AOL delivery errors, temporary deferrals, policy rejections, mailbox failures and RFC header problems. Yahoo 421 4.7.0: Yahoo temporary policy deferralYahoo 421 4.7.0: Yahoo temporary policy deferral. Understand the response, identify ownership, and follow an evidence-based next step. Yahoo 554 Message not allowedResolve Yahoo 554 Message not allowed by using the full response to distinguish authentication, content, reputation, and sender-policy causes.

Primary sources: Yahoo Sender Hub SMTP Error Codes, Yahoo Sender Requirements and Recommendations.