Yahoo Mail 553 5.7.2 [TSS11]: permanent block.

Yahoo permanently blocked the sender. Retrying without remediation will fail.

How to fix 553 5.7.2 [TSS11].

Retrying or final
Final
A 5xx reply. The server will not accept this message. Resending it unchanged fails again.
Who is at fault
Sender
Your authentication, reputation, content, or sending pace.
Severity
CriticalPermanent Block
Permanent553 5.7.2 [TSS11]

TSS11 usually follows spam complaints, compromised accounts, or repeated violations of Yahoo’s bulk sender policies.

Next steps

  1. 1Halt traffic and investigate every stream that sends to Yahoo domains.
  2. 2Close security gaps and document the fixes in a mitigation plan.
  3. 3Provide proof of remediation to Yahoo support before resuming.
  4. 4Send small, monitored batches once Yahoo confirms the unblock.
Yahoo TSS Blocks OverviewYahoo Mail documentationEvery raw SMTP 553 reply

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Other Yahoo Mail fixes

553 5.7.2 [TSS09]Permanent blockFinal
421 4.7.0 [TS01]New or cold IP throttleRetrying
421 4.7.0 [TS02]Complaint rate deferralRetrying
421 4.7.0 [TS03]Reputation holdRetrying
421 4.7.0 [TSS04]Temporary deferralRetrying
451Unresolvable from domainRetrying

In the glossary

Bounce (Hard)Hard bounce is when an email cannot be delivered because the address is invalid or blocked. It is a permanent failure and the address should be removed from your list.
Suppression ListA suppression list is the place your email tool keeps addresses that should not receive messages. It is a permanent "do not send" list that helps you avoid emailing people who have opted out or caused issues in the past.
List HygieneList hygiene is the practice of cleaning your email list by removing bad or inactive addresses. It keeps your list focused on people who still want your emails.
Bounce RateBounce rate is the percentage of emails that could not be delivered to recipients. It shows how many addresses are invalid or blocked compared to the total you tried to send.

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More references.

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