I am getting below error while calling simple graph api from explorer.
https://graph.microsoft.com/v1.0/chats/FEAIj3m6uofGd-3BQ/messages
Even though i have given all the permissions highlighted by Graph Explorer
I have taken reference of No authorization information present on Microsoft Graph API request
The issue might be due there is no admin grant for the above permissions as seen below:
You can also decode your token in https://jwt.ms/ and check in scopes whether the required permissions are available.
Hope this helps.