2018/07/11 by Willem Stam.
Postmastery supports SendGrid clients with multiple webhook endpoints
Postmastery provides delivery monitoring and optimisation services on top of various email delivery environments. Sometimes we offer this service on top of on-premises MTA (like PowerMTA or EmailSuccess) and sometimes on top of cloud-based ESP’s (like Mailchimp or Smartfocus). A prerequisite of delivery monitoring and optimization services, is to get the right data points like […]
Categories: Authentication, General, Sendgrid, Solutions
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