Hi Nyan Cat,
Thanks for reaching out to Microsoft!
For cloud communications resources such as online meetings and virtual events, Microsoft Graph application permissions, tenant administrators must configure an application access policy.
For validating application access policy, you can run this command Get-CsApplicationAccessPolicy to check if the policy created successfully or not.
As per the documentation, ensure to Grant the policy to the user to allow the app IDs contained in the policy to access online meetings on behalf of the granted user.
Grant-CsApplicationAccessPolicy -PolicyName Test-policy -Identity "748d2cbb-3b55-40ed-8c34-2eae5932b22a"
Note: Identity refers to the policy name when creating the policy, but the user ID when granting the policy.
Changes to application access policies can take up to 30 minutes to take effect in Microsoft Graph REST API calls.
While creating subscription make sure to Replace {JoinWebUrl} with the actual URL-encoded value when you specify the resource. Set includeResourceData
to true and provide appropriate values for encryptionCertificate and encryptionCertificateId to subscribe to rich notifications.
Subscribe to online meeting call events
Hope this helps.
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