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Deliverability Letter

451 4.4.62 (ATTR35)

451 4.4.62 ATTR35 Wrong Region

Wrong Region

The message was routed to the wrong Microsoft 365 region.

Misconfigured DNS or routing rules can send mail to an incorrect datacenter. Microsoft rejects the message to prevent loops.

Severity

WARNING

Provider

Microsoft 365 / Outlook

Reference

ATTR35

Last Reviewed

2025-06-01

How to Fix 451 4.4.62 (ATTR35)

Follow these steps to resolve this Microsoft 365 / Outlook SMTP error and restore normal delivery.

  • ✓Verify the recipient’s MX records resolve to the intended geography.
  • ✓Check custom connectors or transport rules that might reroute mail.
  • ✓Coordinate with the recipient admin to confirm regional configuration.
  • ✓Update your smart host list to include regional endpoints.

Helpful Resources

More Microsoft 365 / Outlook SMTP Codes

Keep these related troubleshooting guides handy while addressing 451 4.4.62 (ATTR35).

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451 4.4.4 (ATTR5) – 451 4.4.4 ATTR5 Temporary Server Error
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451 4.7.500 (S77719) – 451 4.7.500 Server Busy (S77719)
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452 4.5.3 (ATTR38) – 452 4.5.3 ATTR38 Mixed Regions
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