SignalR authentication error when using endpoints.MapBlazorHub().RequireAuthorization() - signalr

Question

I have a Blazor server side app that uses authentication. I tried Azure SignalR as suggested by Visual Studio but after that when I am not authenticated I get a blank page instead of the typical not authorized webpage.
If I check the browser debug console, the following message appears:
"Error: Failed to complete negotiation with the server: Error: Unauthorized"
It looks this message is thrown by signalR.
If I change the line endpoints.MapBlazorHub().RequireAuthorization(); to endpoints.MapBlazorHub() in the startup.cs file, it runs as expected.
Any idea on how to fix this?
I tried rolling back the changes made by VS, but it still doesn't work as before.
Thank you
Edit 1: This is the app.cs code for your review:
<CascadingAuthenticationState>
<Router AppAssembly="#typeof(Program).Assembly">
<Found Context="routeData">
<AuthorizeRouteView RouteData="#routeData" DefaultLayout="#typeof(MainLayout)">
<NotAuthorized>
<h1>Restricted Access</h1>
</NotAuthorized>
</AuthorizeRouteView>
</Found>
<NotFound>
<LayoutView Layout="#typeof(MainLayout)">
<p>Page not found</p>
</LayoutView>
</NotFound>
</Router>
</CascadingAuthenticationState>
Edit 2:
This is the startup class
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)
{
services.AddDbContext<IdentityBDContext>(options =>
options.UseSqlServer(
Configuration.GetConnectionString("IdentityBD"),
providerOptions => providerOptions.EnableRetryOnFailure()));
services.AddIdentity<CustomUser, IdentityRole>(options =>
{
options.User.RequireUniqueEmail = true;
options.SignIn.RequireConfirmedEmail = true; //prevents registered users from logging in until their email is confirmed.
}).AddRoles<IdentityRole>()
.AddEntityFrameworkStores<IdentityBDContext>()
.AddDefaultTokenProviders()
.AddUserManager<ERPUserManager>()
.AddSignInManager<ERPSignInManager>();
services.AddAuthorization(options =>
{
options.AddPolicy(SD.Admin, policy => policy.RequireRole(SD.Admin));
options.AddPolicy(SD.POS, policy => policy.RequireRole(SD.POS, SD.Admin));
options.AddPolicy(SD.AllowedTenant, policy => policy.Requirements.Add(new AllowedTenantRequirement(21)));
options.AddPolicy(SD.SysAdmin, policy => policy.RequireRole(SD.SysAdmin));
});
services.AddRazorPages(options =>
{
options.Conventions.AuthorizeAreaFolder("Identity", "/Account/Manage");
});
services.AddServerSideBlazor();
//services.AddSignalR().AddAzureSignalR();
services.AddScoped<AuthenticationStateProvider, RevalidatingIdentityAuthenticationStateProvider<CustomUser>>();
services.AddTransient<ConfigService>();
services.AddTransient<IdentityService>();
services.AddTransient<TenantService>();
services.AddHostedService<TimerUpdate>();
services.AddScoped<IAuthorizationHandler, AllowedTenantHandler>();
//Delete in production
services.AddServerSideBlazor().AddCircuitOptions(options => { options.DetailedErrors = true; });
services.AddScoped<ITenantProvider, WebTenantProvider>();
services.AddDbContext<ERPContext>(options => options
//.UseLoggerFactory(LoggerFactory.Create(builder => builder.AddConsole()))
.UseSqlServer(
Configuration.GetConnectionString("ERPDB")));
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
using (var serviceScope = app.ApplicationServices.GetService<IServiceScopeFactory>().CreateScope())
{
var context = serviceScope.ServiceProvider.GetRequiredService<IdentityBDContext>();
context.Database.Migrate();
}
// Workaround for https://github.com/aspnet/AspNetCore/issues/13470
app.Use((context, next) =>
{
context.Features.Get<IHttpMaxRequestBodySizeFeature>().MaxRequestBodySize = null;
return next.Invoke();
});
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
app.UseDatabaseErrorPage();
}
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.UseAuthentication();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
endpoints.MapBlazorHub().RequireAuthorization();
endpoints.MapControllerRoute("mvc", "{controller}/{action}");
endpoints.MapFallbackToPage("/_Host");
});
}
}