Starting at approximately 4/16, 13:15 UTC time, alerting email notifications for Application Insights alerts in all regions began to experience increasing delays, with latency up to approximately two hours during the peak of the impact window. This included notifications for both Classic and Near-Real-Time alerts, as well as for daily cap warnings & availability tests. Webhooks and other notification paths were not impacted. We've confirmed that email notification latency is now back to normal with no customer impact as of 4/16, 22:42 UTC.
Root Cause: The failure was due to increased load in a dependent service.
Incident Timeline: 4/16, 13:15 UTC through 4/16, 22:42 UTC
We understand that customers rely on Application Insights as a critical service and apologize for any impact this incident caused.