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I have a blazor server app that is a .Net 5.0 application deployed on AWS using AWS Beanstalk. It is a Single Instance deployment, so I currently can't use load balancing (due to current restrictions given to me). The deployed environment platform is "IIS 10.0 running on 64bit Windows Server Core 2019/2.6.3". When i run this locally on VS2019 and local iis server, the app works fine. But once deployed, it throws an error in the browser console:
blazor.server.js:1 [2021-02-19T17:17:03.896Z] Error: Failed to start the transport 'LongPolling': Error
e.log @ blazor.server.js:1
blazor.server.js:1 [2021-02-19T17:17:03.897Z] Error: Failed to start the connection: Error: Unable to connect to the server with any of the available transports. ServerSentEvents failed: Error: 'ServerSentEvents' does not support Binary. LongPolling failed: Error
e.log @ blazor.server.js:1
blazor.server.js:19 [2021-02-19T17:17:03.897Z] Error: Error: Unable to connect to the server with any of the available transports. ServerSentEvents failed: Error: 'ServerSentEvents' does not support Binary. LongPolling failed: Error
e.log @ blazor.server.js:19
blazor.server.js:1 Uncaught (in promise) Error: Cannot send data if the connection is not in the 'Connected' State.
at e.send (blazor.server.js:1)
at e.sendMessage (blazor.server.js:1)
at e.sendWithProtocol (blazor.server.js:1)
at blazor.server.js:1
at new Promise (<anonymous>)
at e.invoke (blazor.server.js:1)
at e.<anonymous> (blazor.server.js:19)
at blazor.server.js:19
at Object.next (blazor.server.js:19)
at blazor.server.js:19The app pretty much won't work, like when i press a button it doesnt do what its told, but some hyperlink buttons work though if its forced to load another page. I started the blazor app using the blazor server template, so I have the _Imports.razor in the project base location, etc.
_host.cshtml
@page "/"
@namespace Space
@{
Layout = null;
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>UI</title>
<base href="~/" />
<link rel="stylesheet" href="css/bootstrap/bootstrap.min.css" />
<link href="css/site.css" rel="stylesheet" />
<link href="_content/MatBlazor/dist/matBlazor.css" rel="stylesheet" />
<!--Blazorise Stuff -->
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/css/bootstrap.min.css" integrity="sha384-9aIt2nRpC12Uk9gS9baDl411NQApFmC26EwAOH8WgZl5MYYxFfc+NcPb1dKGj7Sk" crossorigin="anonymous">
<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.12.0/css/all.css">
<link href="_content/Blazorise/blazorise.css" rel="stylesheet" />
<link href="_content/Blazorise.Bootstrap/blazorise.bootstrap.css" rel="stylesheet" />
</head>
<body>
<component type="typeof(App)" render-mode="ServerPrerendered" />
<div id="blazor-error-ui">
<environment include="Staging,Production">
An error has occurred. This application may no longer respond until reloaded.
</environment>
<environment include="Development">
An unhandled exception has occurred. See browser dev tools for details.
</environment>
<a href="" class="reload">Reload</a>
<a class="dismiss">🗙</a>
</div>
<script src="_framework/blazor.server.js"></script>
<script src="_content/MatBlazor/dist/matBlazor.js"></script>
<!-- blazorise stuff -->
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/[email protected]/dist/umd/popper.min.js" integrity="sha384-Q6E9RHvbIyZFJoft+2mJbHaEWldlvI9IOYy5n3zV9zzTtmI3UksdQRVvoxMfooAo" crossorigin="anonymous"></script>
<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.5.0/js/bootstrap.min.js" integrity="sha384-OgVRvuATP1z7JjHLkuOU7Xw704+h835Lr+6QL9UvYjZE3Ipu6Tp75j7Bh/kR0JKI" crossorigin="anonymous"></script>
<script src="_content/Blazorise/blazorise.js"></script>
<script src="_content/Blazorise.Bootstrap/blazorise.bootstrap.js"></script>
<!-- Workarounds -->
<script src="~/workaround-gradient.js"></script>
</body>
</html>
The startup file
namespace Space
{
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
// This method gets called by the runtime. Use this method to add services to the container.
// For more information on how to configure your application, visit https://go.microsoft.com/fwlink/?LinkID=398940
public void ConfigureServices(IServiceCollection services)
{
var connectionString = AwsParameterStore.GetValue(AwsParameters.AwsConnectString) ??
Configuration.GetConnectionString("DefaultConnection");
services.AddDbContext<UiContext>(options =>
options.UseSqlServer(connectionString));
ConfigureIdentityStuff(services);
services.AddServerSideBlazor();
services.AddScoped<AuthenticationStateProvider, RevalidatingIdentityAuthenticationStateProvider<UiUser>>();
services.AddDatabaseDeveloperPageExceptionFilter();
services.AddBlazorDownloadFile();
services.AddScoped<HttpClient>();
services.AddBlazorise();
services.AddBootstrapProviders();
services.AddFontAwesomeIcons();
services.AddSignalRCore();
}
private void ConfigureIdentityStuff(IServiceCollection services)
{
services.AddDefaultIdentity<UiUser>(options =>
{
options.SignIn.RequireConfirmedAccount = false;
// Password settings.
options.Password.RequireDigit = true;
options.Password.RequireLowercase = true;
options.Password.RequireNonAlphanumeric = true;
options.Password.RequireUppercase = true;
options.Password.RequiredLength = UserRelatedStaticConstDefaults.DefaultMinimumPasswordLength;
options.Password.RequiredUniqueChars = 1;
// Lockout settings.
options.Lockout.DefaultLockoutTimeSpan = UserRelatedStaticConstDefaults.DefaultLockoutTime;
options.Lockout.MaxFailedAccessAttempts = 5;
options.Lockout.AllowedForNewUsers = true;
// User settings.
options.User.AllowedUserNameCharacters =
"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-._@+";
options.User.RequireUniqueEmail = true;
})
.AddRoles<IdentityRole>()
.AddEntityFrameworkStores<UiContext>();
services.ConfigureApplicationCookie(options =>
{
// Cookie settings
options.Cookie.HttpOnly = true;
options.ExpireTimeSpan = TimeSpan.FromMinutes(10);
options.LoginPath = "/Identity/Account/Login";
options.AccessDeniedPath = "/Identity/Account/AccessDenied";
options.SlidingExpiration = true;
});
services.TryAddSingleton<IActionContextAccessor, ActionContextAccessor>();
services.TryAddSingleton<IHttpContextAccessor, HttpContextAccessor>();
services.AddRazorPages(options =>
{
options.Conventions.AuthorizeFolder("/Manage");
});
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
Encoding.RegisterProvider(CodePagesEncodingProvider.Instance);
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
app.UseMigrationsEndPoint();
}
else
{
app.UseExceptionHandler("/Error");
// The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
app.UseHsts();
}
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseRouting();
app.ApplicationServices
.UseBootstrapProviders()
.UseFontAwesomeIcons();
app.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
endpoints.MapBlazorHub();
endpoints.MapRazorPages();
endpoints.MapFallbackToPage("/_Host");
});
}
}
}
My _Imports.razor
@using System.Net.Http
@using Microsoft.AspNetCore.Authorization
@using Microsoft.AspNetCore.Components.Authorization
@using Microsoft.AspNetCore.Components.Forms
@using Microsoft.AspNetCore.Components.Routing
@using Microsoft.AspNetCore.Components.Web
@using Microsoft.AspNetCore.Components.Web.Virtualization
@using Microsoft.JSInterop
@using Space
@using Space.Pages
@using Space.Shared
@using Space.Shared.DataInput
@using Space.Shared.OutputData
@using MatBlazor
@using MatBlazor.Components
@using MatBlazor.Components.MatAutocompleteList
@using ReactiveUI.Blazor
@using Blazorise
@using Blazorise.Components
@attribute [Authorize]
Im not sure whats going on at all. I tried looking it up but i got nothing following multiple suggestions/answers. Could somebody please help!
520
asked Nov 15 '25 05:11
Websockets are needed for Blazor. In the windows beanstalk environment, it is apparently disabled by default.
I enabled them by using this pre-defined config from aws.
commands:
InstallWebsocket:
command: powershell.exe Install-WindowsFeature -name Web-WebSockets
EnableWebsocket:
command: 'C:\windows\system32\inetsrv\appcmd.exe set config "Default Web Site" -section:system.webServer/webSocket /enabled:"True" /receiveBufferLimit:"4194304" /pingInterval:"00:00:10" /commit:apphost'
Put this config in the .ebextensions folder and things work fine.
149
answered Nov 17 '25 17:11
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