We're experiencing a technical issue - email delivery delay

Incident Report for MailerSend

Postmortem

On September 9-10, an infrastructure issue caused an email backlog with delays of up to 5 hours; this was fully resolved as of 7 PM UTC, and all systems are now operating normally. We regret any inconvenience caused.

Posted Sep 11, 2025 - 08:29 UTC

Resolved

Emails are now being processed without delays. We're keeping a close eye on the situation and are ready to intervene for any new events. Content tracking is still disabled until further notice.
Posted Sep 09, 2025 - 16:46 UTC

Monitoring

We are currently experiencing delays in email processing for the MailerSend project. Our team has identified a technical issue that is slowing down the dispatch of outgoing emails, resulting in a backlog and delayed delivery for some users.

We have taken immediate action to reduce system load, and email processing speeds are gradually improving. However, some customers may continue to see slower-than-usual email delivery as we work to fully resolve the issue. We also had to disable content tracking for the time being.

We are actively monitoring the situation and will provide further updates here as we make progress. We apologize for any inconvenience and appreciate your patience.
Posted Sep 09, 2025 - 13:41 UTC

Update

We are continuing to investigate this issue. Email delivery delay is currently 30+ minutes.
Posted Sep 09, 2025 - 11:50 UTC

Update

We are continuing to investigate this issue.
Posted Sep 09, 2025 - 11:47 UTC

Investigating

We are experiencing a technical issue that might cause some delays while sending emails. All of our engineers are working hard to fix the issue as soon as possible.


Thank you for your understanding,
The MailerSend team
Posted Sep 09, 2025 - 10:00 UTC
This incident affected: Email sending (Email sending API, Bulk endpoint, SMTP, Delivery time).