2025/07/04 by Yves-Marie Le Pors-Chauvel.
Orange Spain Announces the End of Its Email Services: What All Senders Need to Know Ahead of September 5, 2025
Orange Spain has officially announced the permanent shutdown of all its email services as of September 5, 2025. What will happen on September 5? All accounts will be permanently closed and deleted—without exception. Even end users will no longer be able to access their messages! This announcement affects anyone using one of the following 17 […]
Categories: Deliverability, Providers
2025/07/03 by Yves-Marie Le Pors-Chauvel.
Unlock Peak Performance: Postmastery's Q1 2025 Email Delivery Benchmark is Here
We are thrilled to announce the release of Postmastery’s Email Delivery Benchmark Q1 2025. This essential study, conducted from January to March 2025, offers a refined analysis incorporating billions of email transactions to deliver an even more robust and comprehensive overview of email performance. What can you find inside? In this edition, we evaluate the most recent delivery trends […]
Categories: Deliverability, Providers
2025/06/20 by Yves-Marie Le Pors-Chauvel.
Outlook Deliverability: A Silent Shift with Serious Consequences
Starting on June 17th, 2025 at 11:10 UTC, multiple high-volume senders – particularly in France – began experiencing a sudden surge in DKIM failures on emails sent to Microsoft domains (Outlook, Hotmail, etc.). These bounces occurred even though SPF and DMARC were properly configured. UPDATE – July, 10 2025 Since the original publication of this […]
Categories: Authentication, Deliverability, Providers
2019/10/07 by Jérôme Gays.
SFR Deliverability: Explaining error codes (GU_EIB) and the ongoing error threshold
Before getting to the actual matter, it is important to brush upon a few relevant chronological events in the past regarding SFR. Even though SFR has been carrying this name since 1987, the many other departments in this group have changed quite a lot ever since. During the past 10 years, SFR has made the […]
Categories: Deliverability, General, Providers
2019/09/04 by Jérôme Gays.
Check your (Power)MTA settings: Numericable and Noos MXs records moved to SFR
In 2014, French ISPs Numericable and SFR merged to become the Altice France group. Numericable was itself the result of a merger between NC Numericable and Noos in 2007. Up to now, mailboxes at these ISPs were managed independently using different MXs and anti-spam protection. Noos and Numericable domains on one end and SFR domains […]
Categories: Authentication, Deliverability, General, Postfix, PowerMTA, Providers
2018/04/10 by Willem Stam.
Delivery issues at LaPoste.net resolved
On Friday April 6, 2018, Postmastery’s Email Delivery Analytics detected serious delivery issues at LaPoste.net. The most frequent SMTP errors we detected were: 421 4.3.2 No system resources 421 4.3.2 All server ports are busy 451 4.7.1 Service unavailable – try again later 421 4.7.0 lpn-prd-vrin0xx Error: too many errors 421 4.4.2 lpn-prd-vrin0xx Error: timeout […]
Categories: Deliverability, General, Providers
2018/04/06 by Willem Stam.
New SMTP replies at Outlook: update your backoff patterns to avoid reputation damage
On April 5th, at 5AM CET, we were alerted by a huge spike in Outlook deferrals. The chart below (copied from Postmastery Delivery Analytics) reveals the deferrals over time: After investigating the issue, Postmastery delivery engineers discovered new SMTP replies at Microsoft domains. These errors are receiver’s side, not related to sender’s reputation. Organization queue quota […]
Categories: Authentication, Deliverability, General, Providers