Error configuring ASP.NET Core web application with Azure App service and Facebook identity

Question

My ASP.Net Core 2.2 application's "Facebook external login setup" is working on my local machine but not working on Azure app service. I get a You can't get an access token or log in to this app from an insecure page. Try re-loading the page as https://error when the application redirects to facebook. However I have set up my application's secure url under facebook configuration=> "Valid OAuth Redirect URIs"(please see screenshot below).

What am I missing?

Startup.cs:

public void ConfigureServices(IServiceCollection services)
{
  services.Configure<ForwardedHeadersOptions>(options =>
  {
    options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
  });
.............

}
public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
      app.UseForwardedHeaders();
    }

Troubleshooting output based on this link:

Header: "X-Client-IP": ["76.187.198.247"]
Header: "X-Client-Port": ["51335"]
Header: "Upgrade-Insecure-Requests": ["1"]
Header: "DNT": ["1"]
Header: "X-WAWS-Unencoded-URL": ["/Identity/Account/Login"]
Header: "CLIENT-IP": ["76.187.198.247:51335"]
Header: "X-ARR-LOG-ID": ["3b69d760-03e7-4199-bec4-38ff77055413"]
Header: "DISGUISED-HOST": ["simplerproductsscrubber.azurewebsites.net"]
Header: "X-SITE-DEPLOYMENT-ID": ["SimplerProductsScrubber"]
Header: "WAS-DEFAULT-HOSTNAME": ["simplerproductsscrubber.azurewebsites.net"]
Header: "X-Original-URL": ["/Identity/Account/Login"]
Header: "X-Forwarded-For": ["76.187.198.247:51335"]
Header: "X-ARR-SSL": ["2048|256|C=US, O=DigiCert Inc, CN=DigiCert SHA2 Secure Server CA|C=US, S=Washington, L=Redmond, O=Microsoft Corporation, CN=*.azurewebsites.net"]
Header: "X-Forwarded-Proto": ["https"]
Header: "X-AppService-Proto": ["https"]
Request RemoteIp: "::ffff:172.16.1.1"
Request Method: "GET"
Request Scheme: "http"
Request Path: "/Identity/Account/Login"
Header: "Connection": ["close"]
Header: "Accept": ["text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3"]
Header: "Accept-Encoding": ["gzip, deflate, br"]
Header: "Accept-Language": ["en-US,en;q=0.9"]
Header: "Cookie": ["ARRAffinity=152c130e21c95ce31be52418aed58ed4a1114b560e108246b2120e2d4dbf27ee; .AspNetCore.Antiforgery.nixphHDAMN4=CfDJ8G1Jn3njIA5IoKC-W8RHjabWwnkwCrPq4ZnU7-ZRlTXbuf8kfpKPQACS5HEylcqol59j-9GJ4AzKFgirMIn8yclO5QSucBnlED9aKjQgAlRrkuZmIZeu8VKT9oOA1V_dvEpjhDoqKxxWrRpfVwST6hU"]
Header: "Host": ["simplerproductsscrubber.azurewebsites.net"]
Header: "Max-Forwards": ["10"]
Header: "Referer": ["https://simplerproductsscrubber.azurewebsites.net/Dashboard"]
Header: "User-Agent": ["Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.169 Safari/537.36"]

Facebook configuration: Valid OAuth Redirect URIs showing my website configured with https:

Answer 1

What worked for me was the solution documented here . An ASPNETCORE_FORWARDEDHEADERS_ENABLED=true app setting also needs to be added in microsoft Azure.

// ConfigureServices

if (string.Equals("true", hostingContext.Configuration["ForwardedHeaders_Enabled"], StringComparison.OrdinalIgnoreCase))
            {
                services.Configure<ForwardedHeadersOptions>(options =>
                {
                    options.ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto;
                    // Only loopback proxies are allowed by default. Clear that restriction because forwarders are
                    // being enabled by explicit configuration.
                    options.KnownNetworks.Clear();
                    options.KnownProxies.Clear();
                });
            }