Unable to read calendar lists with Graph, server error 500

Question

I've got an application that attempts to read calendar data from an outlook.com address. The URL I'm using is:

https://graph.microsoft.com/v1.0/me/calendars?$top=1000&$count=true

I am as certain as I can be that I've got the correct scopes defined. This is what I get back from the token request:

"token_type":   "Bearer",
"scope":    "User.Read Files.ReadWrite.All Mail.ReadWrite Tasks.ReadWrite Calendars.ReadWrite Contacts.ReadWrite Mail.Read",
"expires_in":   3599,
"ext_expires_in":   3599,
"access_token": "EwBYBMl6BAAUBK..."
"refresh_token":    "M.C509_BL2.0..."

I am certain that the GET uses "Content-Type: application/json" and that the auth token is supplied in "Authorization: Bearer EwB...."

The response to the GET is http error 500, internal server error.

The kicker to this is that I do the same call, except "/contactFolders" and that works fine. Mail folders work fine. I have tried various permutations such as specifying "/users/myemailaddress" and getting rid of the parameters. I have tried the beta API. As far as I can tell my outlook.com account has access to calendars. Anyone have a suggestion for me?

One further bit of information - when I use a non-outlook.com address, such as ******@something.onmicrosoft.com, there is no problem.

Answer 1

Hello Jeff McKay,

You're encountering a known issue with the Microsoft Graph API when calling the /me/calendars endpoint for personal Microsoft accounts like Outlook.com, Hotmail.com, or Live.com. This started in late May 2025 and has been reported by many developers.

The request returns a 500 Internal Server Error, even if the token and request are correctly set up.

Work or school accounts (such as those ending in onmicrosoft.com) are not affected.

Microsoft is aware of the issue and is working on a fix. As a temporary workaround, you can avoid the error by skipping two fields that seem to cause the problem: allowedOnlineMeetingProviders and defaultOnlineMeetingProvider.

You can do this by limiting the fields in your request using the $select parameter. Try this request:

GET https://graph.microsoft.com/v1.0/me/calendars?$top=1000&$count=true&?$select=id,name 

This returned calendar data without errors for personal accounts.

You can find more details on this GitHub issue and Microsoft Q&A thread, where many have confirmed that the workaround works.

Hope this helps!

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