How to setup OAuth 2.0 server using loopback.io

Question

I have set up OAuth as per the docs and this link https://strongloop.com/strongblog/node-js-loopback-api-gateway-sample-applications/.

There are a few issues in understanding the usage of the code base and flow based on the options of loopback-component-oauth2. Is there a tutorial that covers each section or a working implementation for Implict, AuthorizationCode, Refresh token, JWT.

I have been able to secure API (eg: /api/Notes) as per docs and it does seem to be blocking requests but is not allowing me to authenticate. More, when I make a request to /oauth/token this API is also throwing Unauthorized 401 errors - both from REST Client like postman and https://loopbacklocalhost/explorer.

I am using loopback 3.0. I am having tough time with the component not documented completely nor having a doc aligned example code. May be I am missing something here.

I have seen this hub repo as well and seems they use passport directly and is documented very less making it difficult to integrate things easily. https://github.com/strongloop/microgateway

Note: I have gone through the following question, the archive repo tests. How to setup OAuth 2.0 server using loopback

Any help is welcome.