Facebook Login Error 191 when use IIS Virtual Directory

Question

I already look other reference article but still can't solve my problem

I own a site named https://shop.yourdomain.com/
Because all my users use Android in App view to browse my site, I manually build a facebook login flow and It works perfectly.
(ref: https://developers.facebook.com/docs/facebook-login/manually-build-a-login-flow )

My problem is below:
I build another website and use IIS virtual directory and use it as a application and URL is
https://shop.yourdomain.com/second-site/

but this time when I use facebook login it will return info below.

API Error Code: 191
API Type OAuthException: OAuthException
API Error Description: The specified URL is not owned by the application Error Message: redirect_uri is not owned by the application.

Already Set Facebook Login APP
1.Setting -> Basic -> Domain add https://shop.yourdomain.com/
2.Facebook login -> Setting -> Valid OAuth Redirect URI add https://shop.yourdomain.com/
3.Redirect Strict Mode -> off

Ever Tried
1.I tried adding https://shop.yourdomain.com/second-site/ to Facebook login -> Setting -> Valid OAuth Redirect URI, but it still didn't work.

2.When I develop this website on my own computer, I use http://localhost:port/ and add http://localhost:port on facebook application setting, and login flow is work.

Has anyone ever encountered a problem of that kind? Please help me. Thank you so much.

Logic Flow Detail is below:

1.After user click 'login' button, then Javascript redirect to Facebook Oauth
location.href = "https://www.facebook.com/v2.12/dialog/oauth ?client_id=XXX &redirect_uri=https://shop.yourdomain.com/second-site/login/facebooklogin/ &state=parameters

2.(Redirect to Facebook Domain)User Login in Facebook or User auth Facebook for my website 3.Facebook HttpGet Back To my WebSite

[HttpGet]
public ActionResult FacebookLogin(string code, string error, string state)
{
    try
    {
        HttpClient client = new HttpClient();
        string facebookUrl = "https://graph.facebook.com/";
        string facebookMethod = "v2.12/oauth/access_token?client_id=XXX
        &redirect_uri=https://shop.yourdomain.com/second-site/login/facebooklogin/
        &client_secret=OOO&code=code;

        var facebookToken = client.GetAsync(facebookUrl + facebookMethod).Result;
        string facebookTokenString = facebookToken.Content.ReadAsStringAsync().Result;
        JObject facebookTokenResult = JObject.Parse(facebookTokenString);

    }
    catch(Exception e)
    {
        //Handle Exception
    }
}

4. facebookTokenResult is below

{
    "error":{
       "message":"Can't Load this website : this website is not include in application domain. If you want to load this website, please add all domain and subdomain in 'application domain'(I translate it in English)",
       "type":"OAuthException",
       "code":191,
       "fbtrace_id":"XXXOOO"
    }
}

Answer 1

I finally find the answer and is not about the any facebook setting.
The problem is the http and https and I only set facebook allow https.
I make a mistake that I put only http url in c# code and that is why facebook always tell me that domain is not allowed.