Previous incidents

Delivery speeds were elevated up to ~5 minutes. They have returned to normal.

We will implement mitigation strategies over the next 24 hours to prevent this from recurring.

There was a brief delay in mail deliveries due to a large spike in traffic. Things have returned to normal, and we are continuing to monitor things.

We have identified a performance issue, and will rectify it so such a spike does not cause delay in the future.

Mail delivery speed has returned to normal.

We experienced a spike in traffic, and our autoscaling wasn't configured aggressively enough to keep up. We've tuned the autoscaling so this will not happen again in the future.

We've migrated to IPs that are more friendly to yahoo deliverability, and systems are returning to normal.

Postmortem posted here: https://improvmx.com/blog/2026-05-15-postmortem-smtp-tls-cert-expiry/