How can I use Stack Overflow for Teams with Stack Exchange API combined?

I have tried creating a stack app and using client ID in Stack Exchange API.

I made a localhost application to implement Stack Overflow for Teams integration and hosted it through ngrok.

Later, I registered hosted app in stack apps and got the client ID and key. I then made an API request using the url

https://stackoverflow.com/oauth?client_id=<ClientID>&scope=read_inbox,no_expiry&redirect_uri=https://fc7d77b5d7b3.ngrok.io/

But then I don't get any response for the API. I assume here's where I have to get access token as response.

Is there anything I am doing wrong in this process?