Angular/SignalR Error: Failed to complete negotiation with the server

connection = new signalR.HubConnectionBuilder()    .configureLogging(signalR.LogLevel.Debug)    .withUrl("http://localhost:5000/decisionHub", {      skipNegotiation: true,      transport: signalR.HttpTransportType.WebSockets    })    .build();

I faced the slimier issue and I fixed it by adding

skipNegotiation: true,transport: signalR.HttpTransportType.WebSockets

in client-side as @Caims mentioned. But I don't think this is the correct solution and feel more like a hack 😊. What you have to do is adding AllowCredentials in server side. Anyway when it's coming to Azure you can't relay on that fix. So no need enable WSS only in client side.

Here is my ConfigureServices method:

public void ConfigureServices(IServiceCollection services){    services.AddCors(o => o.AddPolicy("CorsPolicy", builder => {        builder        .AllowAnyMethod()        .AllowAnyHeader()        .AllowCredentials()        .WithOrigins("http://localhost:4200");    }));    services.AddSignalR();    services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);}

This is my Configure method:

public void Configure(IApplicationBuilder app, IHostingEnvironment env){    if (env.IsDevelopment())    {        app.UseDeveloperExceptionPage();    }    app.UseCors("CorsPolicy");    app.UseSignalR(routes =>    {        routes.MapHub<NotifyHub>("/notify");    });    app.UseMvc();}

And finally this is how I connected from client-side:

const connection = new signalR.HubConnectionBuilder()      .configureLogging(signalR.LogLevel.Debug)      .withUrl("http://localhost:5000/notify", {        //skipNegotiation: true,        //transport: signalR.HttpTransportType.WebSockets      }).build();connection.start().then(function () {    console.log('Connected!');}).catch(function (err) {    return console.error(err.toString());});connection.on("BroadcastMessage", (type: string, payload: string) => {    this.msgs.push({ severity: type, summary: payload });});

I had the same problem, and it turns out that the launchSettings.json in the part where it says signalRchatServer does nothing, the url that worked with me was that of the iisexpress, I say it because there are many places where they say that the url is the one below .