Почему моя функция Azure не может прочитать переменную среды, определенную в классе запуска?

Я хочу прочитать строку подключения, определенную в host.json в моем классе запуска. Проблема в том, что при запуске IConfiguration всегда имеет значение null!

<Project Sdk = "Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net8.0</TargetFramework>
    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
    <OutputType>Exe</OutputType>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>
  <ItemGroup>
    <FrameworkReference Include = "Microsoft.AspNetCore.App" />
    <PackageReference Include = "Azure.Storage.Queues" Version = "12.18.0" />
    <PackageReference Include = "Microsoft.Azure.Functions.Extensions" Version = "1.1.0" />
    <PackageReference Include = "Microsoft.Azure.Functions.Worker" Version = "1.20.1" />
    <PackageReference Include = "Microsoft.Azure.Functions.Worker.Extensions.Http" Version = "3.1.0" />
    <PackageReference Include = "Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" Version = "1.2.0" />
    <PackageReference Include = "Microsoft.Azure.Functions.Worker.Sdk" Version = "1.16.4" />
    <PackageReference Include = "Microsoft.ApplicationInsights.WorkerService" Version = "2.22.0" />
    <PackageReference Include = "Microsoft.Azure.Functions.Worker.ApplicationInsights" Version = "1.1.0" />
    <PackageReference Include = "Microsoft.Extensions.DependencyInjection" Version = "8.0.0" />
    <PackageReference Include = "Newtonsoft.Json" Version = "13.0.3" />
  </ItemGroup>
  <ItemGroup>
    <None Update = "host.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
    </None>
    <None Update = "local.settings.json">
      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
      <CopyToPublishDirectory>Never</CopyToPublishDirectory>
    </None>
    <None Update = "Properties\launchSettings.json">
      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
    </None>
  </ItemGroup>
  <ItemGroup>
    <Using Include = "System.Threading.ExecutionContext" Alias = "ExecutionContext" />
  </ItemGroup>
  <ItemGroup>
    <Compile Update = "Startup.cs">
      <CopyToOutputDirectory>Never</CopyToOutputDirectory>
    </Compile>
  </ItemGroup>
</Project>

Это Function1.csproj

using Microsoft.Azure.Functions.Extensions.DependencyInjection;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Configuration;

[assembly: FunctionsStartup(typeof(MyNamespace.Startup))]

namespace MyNamespace
{
    public class Startup : FunctionsStartup
    {
        public override void Configure(IFunctionsHostBuilder builder)
        {
            var configuration = new ConfigurationBuilder()
                .SetBasePath(Directory.GetCurrentDirectory())
                .AddJsonFile("host.json", optional: true, reloadOnChange: true)
                .AddEnvironmentVariables().Build();

            IConfiguration conf = configuration;

            builder.Services.AddSingleton(conf);
            builder.Services.AddHttpClient();
        }
    }
}

Это класс запуска, который я определил для внедрения зависимостей IConfiguration!

using FirstFunction.dto;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Azure.Functions.Worker;
using Microsoft.Extensions.Logging;
using Newtonsoft.Json;
using System.Globalization;
using System.Text;
using Azure.Storage.Queues;
using Azure.Storage.Queues.Models;
using Microsoft.Extensions.Configuration;
using System.Reflection;

namespace FirstFunction
{
    public class Function1
    {
        private readonly ILogger<Function1> _logger;
        private readonly IConfiguration _configuration;
        private readonly HttpClient _httpClient;

        public Function1(ILogger<Function1> logger)
        {
            _logger = logger;
        }

        public Function1(ILogger<Function1> logger, IConfiguration configuration, HttpClient httpClient) : this(logger)
        {
            _configuration = configuration;
            _httpClient = httpClient;
        }

        [Function("Function1")]
        public async Task<IActionResult> Run([HttpTrigger(AuthorizationLevel.Anonymous, "get", "post")] HttpRequest req)
        {
            #region Catch Error
            string requestBody = string.Empty;
            try
            {
                requestBody = await new StreamReader(req.Body).ReadToEndAsync();
            }
            catch (Exception ex)
            {
                _logger.LogError($"Error reading request body: {ex.Message}");
                return new StatusCodeResult(StatusCodes.Status500InternalServerError);
            }
            #endregion

            string myConnectionString = _configuration["ConnectionStrings:QUEUE_CONNECTION_STRING"];

 return new  OkObjectResult("Data was sent to backend");
        }
    }
}

Это мой метод Azure Function. Код сокращен

using Microsoft.Azure.Functions.Worker;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

var host = new HostBuilder()
    .ConfigureFunctionsWebApplication()
    .ConfigureServices(services =>
    {
        services.AddApplicationInsightsTelemetryWorkerService();
        services.ConfigureFunctionsApplicationInsights();
    })
    .Build();

host.Run();

Это было создано под названием Programm.cs.

Сообщение об ошибке не такое точное, поэтому я его пропустил!

спасибо за помощь !