Hi @DevTKSS,
Welcome to the Auth0 Community!
The reason that you were unable to see any documentation or sample codes for your use case is because all the current Auth0 SDKs are OIDC conformant, which is built on top of the OAuth 2.0 framework, including the client credentials flow needed here.
Our Client Credentials Flow with OIDC documentation also specifies that:
The OIDC-conformant pipeline enables the use of the Client Credentials Flow, which allows applications to authenticate as themselves (rather than on behalf of a user) to programmatically and securely obtain access to an API.
This exchange does not exist in the legacy pipeline; instead, the Resource Owner Password Flow is used to simulate it by creating a service user. We strongly discourage this approach in favor of using the Client Credentials Flow
This means you can still find a workaround by navigating through the ROP flow or by implementing the ASP.NET Core functionalities from our quickstarts ( with many resources and samples that can be found under this page, but the tokens received will still be OIDC complaint, meaning the transition to basic oath claims would require a custom implementation, so unfortunately there is no out of box solution for this, particularly because it implies major security concerns.
Best regards,
Remus