Email Deliverability Insights, Tips & Monitoring Strategies
PowerMTA & Managed Deliverability
2020/11/24 by Willem Stam.
Client case: MailPoet MailPoet was founded in 2011 in France with a simple mission: allow thousands of WordPress website owners to create and send emails from the comfort of their WordPress admin. MailPoet built a simple, intuitive, and rock solid solution to deliver their users’ emails on time, every time. Below you can read more […]
Categories: Case Studies, Deliverability, General, PowerMTA
PowerMTA 5.0: Using a proxy for email delivery
2020/02/14 by Maarten Oelering.
One new thing we are particularly excited about is PowerMTA 5.0 support for forward proxies: this allows delivery from IPs which don’t need to be co-located on the same server or subnet. In this blog post, we will explain this with a few use cases and introduce Postmastery’s MTA proxy for a ready-to-go solution. Use […]
Categories: Authentication, Deliverability, General, PowerMTA
Google Postmaster Tools (GPT) unlocked via Postmastery Delivery Analytics
2019/12/04 by Maarten Oelering.
Postmastery took an important step in their objective to monitor all relevant email delivery metrics in one application: adding Google Postmaster Tools data. What is Google Postmaster Tools (GPT) For senders that monitor their reputation, Google Postmaster Tools (GPT) is an important resource. For those who haven’t yet heard about it, GPT is a website […]
Categories: Authentication, Deliverability, General
SFR Deliverability: Explaining error codes (GU_EIB) and the ongoing error threshold
2019/10/07 by Jérôme Gays.
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
Check your (Power)MTA settings: Numericable and Noos MXs records moved to SFR
2019/09/04 by Jérôme Gays.
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
Delivery issues at LaPoste.net resolved
2018/04/10 by Willem Stam.
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
New SMTP replies at Outlook: update your backoff patterns to avoid reputation damage
2018/04/06 by Willem Stam.
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