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
2018/02/26 by Willem Stam.
AOL and Yahoo merge could impact your email delivery and MTA
A few weeks ago, AOL reported that AOL and Yahoo will come together under the OATH umbrella and merge with the Yahoo email infrastructure to serve both brands. This happened on 20 February 2018, and now all the AOL recipient domains’ MX, including the following, will point to mx-aol.mail.gm0.yahoodns.net: – aol.com – verizon.net – aol.co.uk […]
Categories: Authentication, Deliverability, General, PowerMTA, Providers
2018/02/26 by Willem Stam.
Case study – Why typo domains can cause severe email delivery issues
In our daily email delivery monitoring activities, we recently saw the damage that typo domains can do. In this case study, simple typos in domains caused severe email delivery issues. We will recap what happened and how we solved the issue. Hopefully, other senders can avoid this kind of situation in the future. Postmastery, we […]
Categories: Authentication, Case Studies, Deliverability, General, PowerMTA
2017/11/24 by Willem Stam.
Happy client: SuccessByEmail.com
“I would like to thank the PowerMTA email delivery experts at Postmastery. Postmastery was incredibly responsive to our specific delivery needs and wasted no time in taking a scientific approach to identify specific issues and formulate a path to resolution. From precise data collection and analysis to resolution recommendations and follow up, Postmastery does a […]
Categories: Authentication, Case Studies, General
2017/09/05 by Willem Stam.
Port25 2017 European Summit
Port25 and Postmastery are pleased to invite you to the Port25 2017 European Summit Don’t miss out on this yearly Port25 summit event for people in the world of high volume email delivery. Hear expert speakers from Port25, Postmastery and other companies cover the most topical issues and get all your questions regarding delivery, control, […]
Categories: General
2017/07/13 by Willem Stam.
Choosing the right DMARC policy
Publishing DMARC records is more popular than ever. Even among those that don’t have domains related to sensitive fields, such as financial institutions, that are vulnerable to abuse. Have you thought about the policy that underpins your objectives for DMARC? Do you even have clear objectives for DMARC? DMARC policies DMARC requires three policies: none, […]
Categories: Authentication, DMARC, General