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Deliverability Letter

550 5.1.1

LPN007_416 Invalid Recipient

Invalid Recipient

Laposte confirmed the recipient mailbox does not exist.

Invalid Laposte addresses should be removed immediately. Continued retries quickly degrade the sender score for French ISPs.

Severity

ERROR

Provider

Laposte.net

Reference

LPN007_416

Last Reviewed

2025-06-01

How to Fix 550 5.1.1

Follow these steps to resolve this Laposte.net SMTP error and restore normal delivery.

  • ✓Delete the address after the first bounce and do not retry automatically.
  • ✓Require confirmed opt-in for French recipients to avoid typos.
  • ✓Sync suppression lists across ESPs so retired contacts stay retired.
  • ✓If the address is business critical, ask the recipient to verify spelling or forwarding rules.

Helpful Resources

More Laposte.net SMTP Codes

Keep these related troubleshooting guides handy while addressing 550 5.1.1.

450 4.7.1 – LPN027_503 Service Refused
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450 4.1.8 – LPN007_405 Invalid Sender
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450 4.1.7 – LPN007_411 MX Misconfiguration
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450 4.2.1 – 450 4.2.1 Mailbox Inactive
WARNING

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