Postmaster(y) page

In order to help the sender community, we are glad to share our experiences collected over the years with some ISPs. This page is about the main French Mailbox Provider: This mailbox provider represents millions of active users and is the French biggest free Webmail. Postmastery integrates data from the aggregated Feedback Loop of, through its monitoring tool and its partnership with Signal Spam.

Please find below the table of content of this post:

Market share and history of MBP is the Mailbox Provider which was created in August 2000 by La Poste, the historic operator of mail and parcel delivery in France. Originally, the email addresses were intended to offer a free email address to all French people without them needing to have an Internet subscription.

With several million active accounts, is the first free French Webmail.

Anti-Spam Measures

To protect its messaging infrastructure, relies on multiple filtering solutions, such as Vade (ex-Vade Secure), to optimize filtering of Inbound messages and fight against fraudsters.

Feedback Loop has partnered with Signal Spam and Validity to provide a Feedback Loop in ARF format, as well as an aggregated Feedback Loop, accessible only to both Signal Spam members and Validity Universal Feedback Loop free subscribers.

How does the aggregated Complaint Feedback Loop work and how can we access it?'s aggregated Complaint Feedback Loop is a file in CSV format that contains the volume of complaints by IP and by day. This aggregated Complaint Feedback Loop is available to Signal Spam members and Validity Universal Feedback Loop free subscribers.

How does the Complaint Feedback Loop ARF work and how can I access it?
The ARF Complaint Feedback Loop consists of unit complaint reports in ARF format, sent to a dedicated email address. This ARF Complaint Feedback Loop is accessible to Signal Spam members, and also via the Validity Feedback Loop (1.500$ a year).

Postmastery's customers can track SFR complaint rates in the Reputation Monitor module of the Postmastery Console as well as tracking reputation and complaint data for IP addresses and domains from the world's leading anti-spam solutions including Spamhaus, Cloudmark, Abusix, SURBL, SORBs and Trend Micro. postmaster Technical & SMTP Tweaks

The domain uses the MX server Here are its requirements:

  • 2 concurrent SMTP connections per IP
  • 100 messages per connection recommends authenticating messages with SPF, DKIM and DMARC.

It is important to note that is the only French Mailbox Provider to officially support BIMI. The VMC certificate is not mandatory for that provider.

Common Error SMTP Messages

Here are some examples of error messages indicating a deliverability issue at

450 4.7.1 <XXX.XXXXXXXX.XXXX[WWW.XXX.YYY.ZZZ]>: Client host rejected: Service refuse. Veuillez essayer plus tard. service refused, please try later. LPN027_503

450 4.1.8 <xxx@xxxxxxxx>: Emetteur invalide. Invalid Sender. LPN007_405

450 4.2.1 <>: Recipient address rejected: this mailbox is inactive and has been disabled

450 4.7.0 Service refuse. Veuillez essayer plus tard. service refused, please try later. LPN007_510

550 5.1.1 <>: Adresse destinataire invalide. Invalid recipient. LPN007_416

552 5.2.2 <>: Over quota

550 5.7.1 Email rejected per DMARC policy for xxxxxxxxxx xxxxxxxxxx: Emetteur refuse conformement a la politique DMARC. Email rejected per DMARC policy. LPN007_517

Each SMTP message ends with a Error Code, whose syntax is LPNXXX_XXX. Each Error Code has very precise signification.
Here is a (non-exhaustive) list of existing Error Codes:

As an example, the Error Code LPN007_405 means that the Sending domain has a configuration issue (the sender can’t receive any message) and messages will be temporarily rejected. To fix this issue, you must ensure that all sender addresses accept incoming messages.

Do you have a specific error message you need help with? The Postmastery team is ready to assist, please share some details here.

Abuse Desk & Tech Support

If a problem occurs, has an efficient abuse desk that handles questions related to email deliverability on its infrastructure. All contacts must go through this web form:
When contacting them, be sure to include the following information:

  • date of occurrence of the problem
  • sending IP(s)
  • sending host name(s)
  • sending domain
  • SMTP code returned by

More information
If you want more information about this topic, please send us a message via our contact form.
We are always happy to assist!

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