Fabric GraphQL API with Microsoft App Registration Endpoint, with OAuth Access Token.

Is there a way to make Fabric GraphQL API work microsoft app registration endpoint, with access tokens and not user sign in.

I have a Fabric GraphQL Api in my workspace. I need to expose the API outside with an access token.

I am trying to use the client_secret, generate a bearer token and access the GraphQL data.

The issue I am facing now is:

```
{
"requestId": "****",
"errorCode": "PrincipalTypeNotSupported",
"message": "The operation is not supported for the principal type"
}
```

Microsoft documentation has this [Connect applications to Fabric API for GraphQL](https://learn.microsoft.com/en-us/fabric/data-engineering/connect-apps-api-graphql). Also they have provided a git hub link to [ fabric-samples](https://github.com/microsoft/fabric-samples/blob/main/docs-samples/data-engineering/GraphQL/Python/sample-graphql-app.py). This has already worked as a python script using MSAL library, and I was able to access the graphql data.

I have also read this [Generating token for Fabric Rest api using client secret](https://stackoverflow.com/questions/78226072/generating-token-for-fabric-rest-api-using-client-secret).

I have been able to generate a token using these parameters:

```
URL: https://login.microsoftonline.com/********/oauth2/v2.0/token
Body:
grant_type: client_credentials
client_id: ******
client_secret: *****
scope: 'https://analysis.windows.net/powerbi/api/.default' AND 'https://api.fabric.microsoft.com/.default'
```
Note:
Tried both scopes
As a POST request
The body is in x-www-form-urlencoded with the parameters mentioned above, in postman.

After the token is generated, I am trying another POST request as:

```
URL: https://api.fabric.microsoft.com/v1/workspaces/****/graphqlapis/****/graphql

Headers:
Authorization: Bearer {Token generated above}
Content-Type: application/json

Body
GraphQL type:
{
"query": "{ table1s { items { col1 } } }"
}
```

In the app registration I have given permissions as the doc suggests. Also, I have tried all of the authentications, 'Mobile and desktop applications', 'Web' etc, the
'Allow public client flows' setting is also enabled. I am putting 'http://localhost:52189' as the redirect URL, this was for testing it with the python code as the link above suggested.

The App is an admin in my fabric workspace. I am also the owner, and the cloud Application Administrator of the app.

What more am I missing?