Intermittent Missing Event Notifications from Microsoft Graph API Webhook

I am writing to report an issue we are experiencing with missing event notifications from our Microsoft Graph API webhook. Despite having correctly configured subscriptions and logging, we have observed that some events are not being delivered to our endpoint. Below are the details of the problem:

Issue Description: Our webhook setup correctly handles and logs incoming notifications, and our subscriptions are configured to cover created, and updated events for messages. However, we have noticed intermittent missing events, which are not reaching our service.

Details:

• Product: Microsoft Graph API
• Resource: /users/{user_id}/messages
• Event Types: created, updated
• Time of Occurrence: Intermittent, no specific pattern
• Error Messages: None
• Troubleshooting Steps Taken:
  • Verified Active Subscriptions:
    • Ensured that all webhook subscriptions are active and have not expired.
  • Implemented Detailed Logging:
    • Established detailed logging for all received events. Our logs confirm that our API correctly handles and logs every event it receives.
  • Ensured Endpoint Accessibility:
    • Confirmed that our endpoint is consistently accessible and successfully processes incoming notifications.
  • Checked for Throttling:
    • Verified that our service has not been throttled during the times of the missing events. Our logs indicate that the service successfully handled events within a matter of seconds.

Impact: This issue is affecting our ability to reliably synchronize email data in real-time, which is critical for our application's functionality.