Laposte.net SMTP Error Codes
Master French email delivery with our guide to Laposte.net SMTP errors. Understand LPN error codes, connection limits, and France's unique email requirements.
🇫🇷 About Laposte.net
Platform Overview
- • France's first and largest free webmail provider
- • Created in August 2000 by La Poste (French postal service)
- • Originally offered free email without needing Internet subscription
- • Millions of active @laposte.net accounts
- • Uses Vade (ex-Vade Secure) for spam filtering
Unique Features
- • Only French ISP with official BIMI support
- • VMC certificate not mandatory for BIMI
- • Partners with Signal Spam for FBL
- • Strict sender validation requirements
📊 Understanding LPN Error Codes
Laposte.net uses a unique error code system with the format LPNXXX_XXX. Each SMTP error message ends with a Laposte.net Error Code that has a specific meaning:
- LPN027_503 - Service temporarily refused
- LPN007_405 - Sender configuration issue
- LPN007_416 - Invalid recipient address
- LPN007_510 - Service refused (content/policy)
- LPN007_517 - DMARC policy rejection
Laposte.net SMTP Error Codes Explained
450 4.7.1
LPN027_503Client host rejected: Service refuse / service refused
Your IP or host has been temporarily blocked by Laposte.net. Error includes "Veuillez essayer plus tard / please try later". Usually due to reputation issues or rate limiting.
How to Fix:
- ✓Wait and retry later as suggested in the error message
- ✓Check your sending IP reputation
- ✓Reduce sending volume and implement proper rate limiting
- ✓Verify you're following Laposte.net connection limits (2 concurrent, 100 msgs/connection)
450 4.1.8
LPN007_405Emetteur invalide / Invalid Sender
The sending domain has a configuration issue - specifically, the sender address cannot receive messages. Laposte.net requires all sender addresses to be able to receive mail.
How to Fix:
- ✓Ensure all sender addresses can receive incoming messages
- ✓Check that your domain has valid MX records
- ✓Verify your mailbox isn't rejecting test messages
- ✓Don't use no-reply addresses that reject all mail
450 4.2.1
Recipient address rejected: mailbox is inactive and disabled
The recipient's Laposte.net mailbox has been deactivated due to inactivity or user request.
How to Fix:
- ✓Mark as soft bounce in your system
- ✓Suppress after multiple consecutive failures
- ✓Consider removing after 3-5 attempts over several weeks
- ✓Implement re-engagement campaigns to prevent inactivity
450 4.7.0
LPN007_510Service refuse / Service refused
Generic service refusal, often related to content filtering or temporary policy blocks.
How to Fix:
- ✓Review email content for spam triggers
- ✓Check authentication (SPF, DKIM, DMARC)
- ✓Verify compliance with French anti-spam laws
- ✓Wait and retry with exponential backoff
550 5.1.1
LPN007_416Adresse destinataire invalide / Invalid recipient
The recipient email address does not exist at Laposte.net. This is a permanent failure.
How to Fix:
- ✓Remove this address from your mailing list immediately
- ✓Do not retry sending to this address
- ✓Implement proper bounce handling
- ✓Use double opt-in to verify addresses
552 5.2.2
Mailbox over quota
The recipient has exceeded their Laposte.net storage quota and cannot receive new messages.
How to Fix:
- ✓Treat as a soft bounce
- ✓Retry over several days
- ✓Suppress after 3-5 consecutive failures
- ✓Consider alternative contact methods for important messages
550 5.7.1
LPN007_517Email rejected per DMARC policy
Your email failed DMARC authentication and the domain has a reject policy. Laposte.net strictly enforces DMARC policies.
How to Fix:
- ✓Ensure SPF and DKIM are properly configured
- ✓Verify DMARC alignment (domain in From header matches authentication)
- ✓Check your DMARC policy settings
- ✓Use proper subdomain alignment if sending from subdomains
Laposte.net Best Practices
Connection Limits
- •Maximum 2 concurrent SMTP connections per IP
- •Up to 100 messages per connection
- •Use single MX server: smtpz4.laposte.net
- •Implement proper connection pooling
Authentication
- •SPF, DKIM, and DMARC are required
- •BIMI supported (VMC not mandatory)
- •Only French provider with official BIMI support
- •Strict DMARC enforcement
French Compliance
- •Follow French anti-spam laws (LCEN)
- •Provide clear unsubscribe in French
- •Respect opt-in requirements
- •Include sender identification
List Management
- •Access feedback loops via Signal Spam
- •Available through Validity Universal FBL
- •Monitor aggregated complaint data
- •Remove complainers promptly
Technical Configuration
Laposte.net Connection Settings
MX: smtpz4.laposte.net
max_concurrent_connections = 2
max_messages_per_connection = 100
SPF: Required
DKIM: Required
DMARC: Required (strictly enforced)
BIMI: Supported (VMC optional)
Complaint Feedback Loops
Laposte.net partners with Signal Spam and Validity to provide comprehensive feedback loops. Some monitoring tools like Postmastery integrate data from the aggregated FBL through their partnership with Signal Spam.
📈 Aggregated FBL (CSV)
Daily complaint volumes by IP address, available to:
- • Signal Spam members
- • Validity Universal FBL subscribers (free)
- • CSV format with daily aggregates
📧 ARF Feedback Loop
Individual complaint reports in ARF format:
- • Signal Spam members
- • Validity FBL ($18+ per year)
- • Real-time ARF reports
French Email Requirements
📜 Legal Compliance (LCEN)
French law requires:
- Clear sender identification in every email
- Easy unsubscribe mechanism (in French)
- Explicit consent for marketing emails
- Data protection compliance (RGPD/GDPR)
🌐 Language Considerations
- Include French language options in emails
- Error messages are bilingual (French/English)
- Support communications should be in French
- Consider French timezone for sending times
Laposte.net Resources
📞 Contacting Laposte.net Support
When contacting Laposte.net's efficient abuse desk, include:
- ✓Date and time of occurrence
- ✓Sending IP address(es)
- ✓Sending hostname(s)
- ✓Sending domain
- ✓Complete SMTP error code with LPN reference
Need Help with French Email Delivery?
Navigating French email requirements and Laposte.net's unique LPN error system can be complex. Let us help you optimize your email delivery to French recipients.