Azure Batch Transcription Rest API with ENTRA ID and managed identities is not working

@Lakshmi Siva Kumar Viswanadula For entra, i think you need to create a custom domain. As per this documentation.

To configure your Speech resource for Microsoft Entra authentication, create a custom domain name and assign roles.

Since creating a sub domain is irreversible, you might want to create a new resource and try the scenario with custom domain creation, disabling local authentication on the resource and assigning the required roles as mentioned in the above document.

To get a token for REST API, try the following for authorization request.

Then calling the STS url({endpoint}/speechtotext/v3.2-preview.2/transcriptions) with additional scope for transcriptions API.

Additional scope:

Provide an access token from the JWT returned by the STS of this region. Make sure to add the management scope to the token by adding the following query string to the STS URL: ?scope=speechservicesmanagement

I hope this helps!!