How to set permission in role to use graph API for sending notification in MS Teams Channel

Question

I generated Access token using following API from POSTMAN

https://login.microsoftonline.com/6e93a626-8aca-4dc1-9191-ce291b4b75a1/oauth2/v2.0/token

I added the token as Bearer Token in following API to send message in MS teams channel in POSTMAN

https://graph.microsoft.com/v1.0/teams/94e00976-e23a-4293-a06b-b030b8ec815f/channels/19%3AkYlMe6UMA12Q5KnDXRu8XgrnqV9RYNXwQMYN4g6BONg1%40thread.tacv2/messages

But I am getting following error.

I am unable to set permission for my application.

Can you please guide me to get permission for my application?