I am using rest APIs to do Oauth 2.0( code flow) to get AccessToken.
with the help of the token I can fetch calendar events but not able to create event into the calendar got an Invalid Auth token error.
URL: https://graph.microsoft.com/v1.0/me/events
the scopes are https://graph.microsoft.com/Calendars.ReadWrite Calendars.ReadWrite.Shared offline_access
I have granted delegate Permissions 
still getting this error following errors

{"error":
{"code":"Authorization_RequestDenied",
"message":"Insufficient privileges to complete the operation.",
"innerError": {"date":"2021-06-07T18:43:59","request-id":"78d2ecbf-6c88-4ae1-a9d5-207a1162463c","client-request-id":"78d2ecbf-6c88-4ae1-a9d5-207a1162463c"}}}