Microsoft Graph API: How to access guest user calendar events using API?

Question

Hi,

I am working on an outlook calendar integration with our application. I have got a business/organisation Microsoft account.

So far I have registered an application in the Azure active directory admin centre.
I have added API Following API permissions

Then I used the following API call to get the access token

https://login.microsoftonline.com/{Tenant_ID}/oauth2/v2.0/token

I received a Bearer token and used it for following API call

https://graph.microsoft.com/v1.0/users

I am getting list of users and one of then is guest user. Now I want to get calendar events of this guest user and I am using following API call

https://graph.microsoft.com/v1.0/users/{user_id}/calendars
https://graph.microsoft.com/v1.0/users/{user_id}/calendars/events
https://graph.microsoft.com/v1.0/users/{user_id}/events

I am getting following error only for guest users but I am getting right data for Member users.

AadGuestPft token doesn't contain the permissions required by the target API.

Any Idea what is going on here?

Answer 1

Hi @Sanket Khot

Guest users don't have Exchange mailboxes in your enterprise tenant, so you can't list calendar events for guest users in your tenant, you can only get calendar events in the original tenant where the guest user is located.

Change /{tenant id} to /common, and then log in with your guest user to get a delegation token.

Call the graph API:

https://graph.microsoft.com/v1.0/me/events

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Answer 2

Guests do not have a mailbox within the resource tenant, so you cannot query Calendar data for them.