Yahoo OAuth Redirect not working

Question

Kind of hitting a wall here. I setup my callback domain to be my ngrok instance (paid account). My redirect request to Yahoo's auth looks like this:

"https://api.login.yahoo.com/oauth2/request_auth?client_id=fakeclientid--&redirect_uri=https://myname.ngrok.io/api/authentication_handler&response_type=code&language=en-us"

I'm redirecting to that as so:

return new RedirectResult(yahooOauthUrl);

I correctly get redirected, enter my credentials, get logged into Yahoo, but I'm presented with a screen on Yahoo's side with this:

What Yahoo Shows

If I publicly submit a GET/POST request to my redirect URI in postman or through Chrome, I get a request hitting my localhost fine. I've also verified that my Yahoo app has the exact same callback domain of:

myname.ngrok.io

The code to handle my callback request is here:

// GET/POST api/authentication_handler
[HttpGet]
[Route("/api/authentication_handler")]
public HttpResponseMessage HandleAuthentication(string code)
{
    return string.IsNullOrWhiteSpace(code) 
        ? new HttpResponseMessage(HttpStatusCode.InternalServerError) 
        : new HttpResponseMessage(HttpStatusCode.OK);
}

Am I missing anything obvious?

Answer 1

So, found out what was happening. Make sure you clear your cookies or use incognito mode when testing this kind of stuff. Seems as if Chrome was caching my calls since I was never even hitting the initial endpoint after changing some code and testing this out. Once I did I was able to find that the client_id wasn't properly getting set due to the way I was using string literals.