Hi @Kripa
If you are not the organizer or attendee of the target meeting, then you will not be able to access the meeting. Currently, only the organizer or attendee of the meeting is supported to access the target meeting.
In addition, if you are getting the meeting information joined by other users, the target user must also be the organizer or attendee of the meeting, otherwise the access will be blocked.
By the way, do not call GET /users/{userId}/onlineMeetings?$filter=JoinWebUrl%20eq%20'{joinWebUrl}'
API in Graph Explorer, because this endpoint is only available for application permissions, you should request an access token using the client credentials flow in Postman and test.
Hope this helps.
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