US Email Ingest Errors

This incident has been resolved.

Between 12:55 UTC and 13:07 UTC, customers may have experienced email sending failures in the US region. A deployment of new code caused our sending pipeline to temporarily reject some email submissions with HTTP 500 or SMTP 451 errors (~ 2.5% of requests). Our team quickly identified the issue, rolled back the deployment, and restored normal service. Traffic was immediately shifted from the affected US region to the non impacted region to further mitigate customer impact while the rollback took place.