Email delivery issues to outlook/microsoft

Everything is back to normal. We've monitored for 24 hours and confirmed stable email delivery to all Microsoft inboxes. This incident is now closed.

The issue appears to be resolved on Microsoft's side. We no longer see rate limiting errors in our logs. We are currently reverting temporary mitigations we put in place, which may cause minor delivery delays in the short term. We will keep monitoring to ensure delivery remains stable.

Delivery rates are improving. Emails are being delivered, but some delays to Microsoft inboxes may still occur.

This is a widespread issue on Microsoft's side, many email senders across the internet are experiencing the same rate limiting since February 24th, as reported on Microsoft's own community forums.

Microsoft is rate-limiting our sending IP, causing emails to Outlook, Hotmail, and Live inboxes to be temporarily delayed or bounced.

What we've done so far:

Deployed mitigations with our email provider to reduce sending volume through the affected IP
Reduced duplicate failure notifications to customers
Reached out to Microsoft to resolve the rate limit

We continue to monitor closely and will provide further updates.

We have identified the issue and are working with our service providers and microsoft to resolve the issue. We are also investigating longer term solutions that will take more time to implement.

We are investigating reports of problems with email delivery specifically to Outlook.