Resolved
Our backend email service has processed all email notifications. Metrics have returned to normal.
Monitoring
A configuration fix for our backend email service has been deployed. We will be monitoring metrics.
Identified
The root cause of the problem has been identified. A configuration fix for our backend email service is now in progress.
Investigating
A problem with email notifications via SendGrid has been reported and confirmed. An escalation engineer has been paged and is actively investigating.