How to Fix HTTP 403 Error When Creating Events in a Shared Teams Calendar via Microsoft Graph
Question details
The user needs to resolve an HTTP 403 Forbidden error returned when attempting to create an event in a shared Teams group calendar using the Microsoft Graph API.
- Product
- Microsoft Graph API
- Device & OS
- not provided
- Scenario
- Automating or integrating event creation within a shared calendar associated with a Microsoft Teams group via API requests.
- Observed behavior
- The Microsoft Graph API request fails with an HTTP 403 error, likely because application-level permissions are not supported for this specific shared or group calendar scenario.
Ensure you have administrator access to the Microsoft Entra ID (formerly Azure AD) portal to review your application's API permissions, and keep a copy of your exact API request payload and error response handy.
Verify Supported Microsoft Graph Permissions and Adjust Access
Check the Microsoft Graph documentation to ensure your application has the appropriate delegated permissions, as application-level permissions may not be supported for Teams group calendars.
Many Microsoft 365 group and Teams shared calendars do not support application permissions (where the app runs as a background service without a signed-in user) for creating events. In these cases, a 403 Forbidden error is returned.
To resolve this, you may need to switch your authentication flow to use Delegated permissions, which operate on behalf of a signed-in user who has access to the shared calendar.
Consult the official Microsoft Graph API reference for the 'Create event' endpoint to verify the exact permission scopes required for group calendars.
Log into the Microsoft Entra admin center, navigate to 'App registrations', and select your application.
Go to the 'API permissions' blade. If you are using Application permissions (e.g., Calendars.ReadWrite), try adding Delegated permissions (e.g., Group.ReadWrite.All) instead.
After updating the permissions, click 'Grant admin consent for [Your Organization]' to ensure the permissions are actively applied to your application.
Submit Request Details to Microsoft Graph Support
If permission adjustments do not resolve the issue, contact Microsoft Support with your specific token and payload to identify supported alternatives.
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Frequently Asked Questions
Why does Microsoft Graph return a 403 error for Teams shared calendars?
An HTTP 403 Forbidden error usually indicates that the application lacks the correct permissions, or that the specific calendar endpoint does not support application-level permissions (running without a signed-in user) for creating events in that particular type of group.
Can I use Application permissions to create events in any Microsoft 365 calendar?
No. While Application permissions work for many user calendars, Microsoft Graph has restrictions on certain shared and Microsoft 365 group calendars (like those linked to Teams) where delegated permissions are strictly required.
How do I check my current app permissions for Microsoft Graph?
Log into the Microsoft Entra admin center, go to 'App registrations', select your application, and click on 'API permissions'. Here you can see whether you have Delegated or Application permissions configured for Microsoft Graph.
