450 4.1.8
LPN007_405 Invalid Sender
Laposte rejected the sender address because it cannot receive mail.
Laposte requires functional reply-to addresses. Using no-reply mailboxes that bounce inbound mail results in LPN007_405.
Severity
WARNING
Provider
Laposte.net
Reference
LPN007_405
Last Reviewed
2025-06-01
How to Fix 450 4.1.8
Follow these steps to resolve this Laposte.net SMTP error and restore normal delivery.
- ✓Ensure every From or Reply-To address accepts mail and is monitored.
- ✓Publish MX records for all sending domains.
- ✓Avoid auto-deleting replies; route them to a monitored mailbox instead.
- ✓If you need a no-reply address, add an alternate support contact in the footer.
Helpful Resources
More Laposte.net SMTP Codes
Keep these related troubleshooting guides handy while addressing 450 4.1.8.
Still experiencing Laposte.net delivery issues?
Run your domain through our free deliverability tools or book a session with Bento's deliverability specialists.