Angular / .net core web Api hosted on IIS - HTTP Error 499 "No reason phrase" when trying to make a get request with https

Question

I hosted my .net core 5.0 web api on a windows server with IIS and HTTPS.I made some test requests with postman and all of them worked PERFECTLY, Now i tried to make the requests within my angular application and the httpclient from angular. but nothing works.

This is my code for making the request:

1. Define the header

   const httpOptions = { headers: new HttpHeaders({ 'Content-Type': 'application/json', 'Authorization': 'Basic ' + btoa('xyz:xyz') }) };

2. Make the request:

   this.http.get("https://148.xxx.xxx.xxx:10023/simmanager/" + number, httpOptions).subscribe(r=>{ console.log(r)}, err =>{ console.log(err));

The result in the browser console is: browser errors

I have no idea? Is it a CORS error? Is it because of false hosting? I am hosting the EXACT same API with only HTTP and .net core 3.1 and it works. Maybe i made a mistake with CORS in .net core 5? Thank you for helping me out!

This is my cors policy:

Startup.cs Configure Method:

app.UseCors(x => x
            .AllowAnyMethod()
            .AllowAnyHeader()
            .SetIsOriginAllowed(origin => true) // allow any origin
            .AllowCredentials()); // allow credentials

Startups.cs ConfigureServices Method:

            services.AddCors();

Answer 1

You could try to remove webdev module from iis:

1. Open iis server, select server name.

2. Double click on modules

3. Select webdevmodule and choose remove from action pane:

Then add custom headers as below to the site web.config file:

<httpProtocol>
  <customHeaders>
    <add name="Access-Control-Allow-Origin" value="*"/>
    <add name="Access-Control-Allow-Headers" value="Content-Type"/>
    <add name="Access-Control-Allow-Methods" value="POST,GET,OPTIONS,PUT,DELETE"/>
  </customHeaders>
</httpProtocol>