[West US] Delayed email delivery caused by Azure availability issues

This incident has been resolved.

The failover infrastructure is operating correctly, and our telemetry indicates that previously delayed emails have now been delivered with signatures applied. The issue appears to be mitigated, however, our 24/7/365 Monitoring Team will continue to closely observe the service. We will switch back to the primary Azure infrastructure once it becomes available. This transition will be transparent to customers and will not cause service interruptions. No customer action is required.

We will also work with Microsoft to determine the root cause of the regional service issue.

After switching over to tertiary infrastructure, Azure is now processing our requests correctly and email delivery speed has returned to normal. Emails that were delayed on the previous two environments should be delivered soon with signatures applied. We are continuing to investigate why the primary Azure resources are unhealthy; however, all new emails are currently being processed through our regional failover services and are being delivered in a timely manner with signatures.

At this time, we have not received any customer reports related to this issue, but as a precaution, we are failing over to redundant infrastructure within the same region.

Microsoft Azure is currently experiencing availability issues in the West US region, which may affect email delivery speed for customers using server-side signature rules. We are currently investigating the problem.