with this configuration, when I run on localhost both projects at the same time it works as expected (communicating with API to Web project and get data). even if I run the API in Docker and web in localhost, also it works(communicating with API to Web project and get data). But when I run API and Web Project in Docker, individually work, (Works) API:http://localhost:6969/swagger/index.html (Works) WEB:http://localhost:8080/Account/Login but they can not communicate with API to Web project and web app can not get results, and gets an error on logger: Connection refused. (Why?) help me to resolve it, I use Docker-Compose file to run both projects on Docker.

builder.Services.AddCors(options => { options.AddPolicy(“AllowWebApp”, builder => { builder .WithOrigins(“http://localhost:5759”, “http://localhost:8080”, “https://localhost:44361”) // Replace with the URL of your web app .AllowAnyMethod() .AllowAnyHeader(); }); });

API

`
builder.Services.AddSingleton<IAuthorizationHandler, PostViewRequirementHandler>();
builder.Services.Configure(builder.Configuration.GetSection(“Kestrel”));

builder.Services.AddControllers();
builder.Services.AddEndpointsApiExplorer();
builder.Services.AddSwaggerGen();
builder.Services.AddMediatR(cfg => { cfg.RegisterServicesFromAssembly(typeof(Program).Assembly); });

var app = builder.Build();

Log.Information("Application Starting...");
  
app.UseSwagger();
app.UseSwaggerUI();

app.UseHttpsRedirection();

app.UseCors("AllowWebApp");

app.UseAuthorization();

app.MapControllers();
Log.Information("API Application Running...");

app.Run();`

Web app

`

    public async Task<Post[]> GetPostsAsync(string token)
    {
        try
        {
            _httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);

            var r = _httpClient.DefaultRequestHeaders.Authorization.ToString();
            _logger.LogInformation($"Authorization: {r}");

            var c = _httpClient.BaseAddress.ToString();
            _logger.LogInformation($"BaseAddress: {c}");

            var response = await _httpClient.GetAsync("Post");
            response.EnsureSuccessStatusCode(); // Throw exception if not success

            var content = await response.Content.ReadAsStringAsync();

            _logger.LogInformation(content);

            return JsonConvert.DeserializeObject<Post[]>(content);
        }
        catch (HttpRequestException ex) when (ex.StatusCode == HttpStatusCode.Unauthorized)
        {

            var r = _httpClient.DefaultRequestHeaders.Authorization.ToString();
            _logger.LogInformation($"Authorization: {r}");
            // Handle 401 Unauthorized exception
            // Redirect to login page or display a message asking the user to login again
            // throw; // Rethrow the exception if you want to handle it further up the call stack
            _logger.LogError(ex.Message);
            _logger.LogError(ex.StackTrace);
            _logger.LogError(ex.StatusCode.ToString());
            return null; // Return null if an exception occurs
        }
        catch (Exception ex)
        {
            // Handle other exceptions
            // throw;
            var c = _httpClient.BaseAddress.ToString();
            _logger.LogInformation($"BaseAddress: {c}");
            _logger.LogError(ex.Message);
            return null; // Return null if an exception occurs
        }
    }`

Docker-Compose

`version: “3”
services:
api:
build:
context: .
dockerfile: Stackoverflow.API/DockerFile
image: deboraj/stackoverflow.api
env_file:
– Stackoverflow.API/api.env
volumes:
– stackoverflow-api-log:/app/Logs
ports:
– “6969:80”
entrypoint: [“dotnet”, “Stackoverflow.API.dll”]

web:
    build: 
        context: .
        dockerfile: Stackoverflow.Web/DockerFile
    image: deboraj/stackoverflow.web
    
    env_file: 
        - Stackoverflow.Web/web.env
    volumes:
        - stackoverflow-web-log:/app/Logs
    ports:
        - "8080:80"
    environment:
         - API_URL=http://localhost:6969/v3/
    entrypoint: ["dotnet", "Stackoverflow.Web.dll"]

volumes:
stackoverflow-api-log:
external: true
stackoverflow-web-log:
external: true
`

when I run the Docker Compose file my API and Web App both should be works, my web app is Dependable on API to get Value.