The queues are caught up, and we are observing normal mail flow at this time.
The rate limiting experienced this morning was a response to abusive mail volume that was exacerbated by the reduction in Microsoft servers communicating with Shield. We will continue to monitor our queues through the business day to ensure processing is stable.
Posted Oct 20, 2026 - 14:55 EDT
Identified
It appears that a reduction in the number of Microsoft servers communicating with Shield this morning contributed to the per-server volume spike.
The team has mitigated the connection timeouts and rate limits, and the queues are draining. We do not have an exact time for when the queues will be emptied, but it appears it should be within the hour, most likely sooner.
We are continuing to investigate with a priority of restoring stable and expected mail flow.
Posted Oct 20, 2026 - 14:21 EDT
Update
We are continuing to investigate this issue.
Posted Oct 20, 2026 - 13:21 EDT
Investigating
We are investigating reports of connection timeouts or rate limiting with some domains using Shield. This is not affecting all mail flow.