2019/09/04 by Willem.
Numericable and Noos MXs records moved to SFR: check your (Power)MTA settings
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 […]
Categories: Authentication, Deliverability, General, Postfix, PowerMTA, Providers
2018/04/10 by Willem.
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, Providers
2018/04/06 by Willem.
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