Graph API: Calendars endpoint doesn't work (returns an empty array) for some users

Question

The endpoint https://graph.microsoft.com/v1.0/users/<user email address>/calendars works for most users but for some it returns an empty array. We cannot figure out what is different about these users (they definitely have calendars and we can get the calendars via, e.g., powershell)

Answer 1

• Outside of your custom application or Powershell, i would suggest you to test the same API call in POSTMAN or Graph Explorer with the same AAD workflow that you implemented. This will help you to isolate the issue and see whats coming back from the server as well.
• If you can repro the issue, share the requestid, timestamp from the response and additional info (say, error info etc) for analysis