Run ASP.NET webapi selfhost on Linux

Question

I've created an ASP.NET web api on Windows that returns some test data as XML. I have installed the Nuget package Microsoft ASP.NET Web Api Self Host and in the web api I have configured a Selfhost with the port 1234. I have used the following documentation:

https://learn.microsoft.com/de-de/aspnet/web-api/overview/older-versions/self-host-a-web-api

I ran Visual Studio as an administrator and I also ran the web api. In the browser I entered localhost:1234/api/product/1. It works.

I'm trying to run this on Linux. The whole solution was copied to Linux and executed with MonoDevelop. When starting the web api and entering localhost:1234/api/product/1 in the browser, no data is returned. It loads infinitely.

Here is the code for the controller:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;
using WebServiceTest.Models;

namespace WebServiceTest.Controllers
{
    public class ProductsController : ApiController
    {
        Product[] products = new Product[]
        {
            new Product { Id = 1, Name = "Tomato Soup", Category = "Groceries", Price = 1 },
            new Product { Id = 2, Name = "Yo-yo", Category = "Toys", Price = 3.75M },
            new Product { Id = 3, Name = "Hammer", Category = "Hardware", Price = 16.99M }
        };

        [Route("api/product/getall")]
        [HttpGet]
        public IEnumerable<Product> GetAllProducts()
        {
            return products;
        }

        [Route("api/product/{id}")]
        [HttpGet]
        public IHttpActionResult Get(int id)
        {
            var product = products.FirstOrDefault((p) => p.Id == id);
            if (product == null)
            {
                return NotFound();
            }
            return Ok(product);
        }
    }
}

Here is the code of the WebApiConfig class:

using System;
using System.Web.Http;
using System.Web.Http.SelfHost;

namespace WebServiceTest
{
    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            // Web-API-Konfiguration und -Dienste
            var selfHostConfig = new HttpSelfHostConfiguration("http://localhost:1234");

            // Web-API-Routen
            selfHostConfig.MapHttpAttributeRoutes();

            using (HttpSelfHostServer server = new HttpSelfHostServer(selfHostConfig))
            {
                server.OpenAsync().Wait();
                Console.WriteLine("Press Enter to quit.");
                Console.ReadLine();
            }
        }
    }
}

How do I manage to run the web api on Linux?