Failed to start the connection: Error: WebSocket failed to connect

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Error: Failed to start the connection: Error: WebSocket failed to connect. The connection could not be found on the server, either the endpoint may not be a SignalR endpoint, the connection ID is not present on the server, or there is a proxy blocking WebSockets. If you have multiple servers check that sticky sessions are enabled.

WebSocketTransport.js:49 WebSocket connection to 'ws://xxxxxx/production/web-services/hubs/spreadhub' failed:

Angular.ts

 ngOnInit(): void {

      // For signalR Hub connection
      this.connection  = new HubConnectionBuilder()  
      .withUrl('http://xxx.xxx.com/production/web-services/hubs/spreadhub', {  // localhost from **AspNetCore3.1 service**
        skipNegotiation: true,
        transport: signalR.HttpTransportType.WebSockets
      })  
      .build();

        this.connection.on('dataReceived', (data: string) => {
          var model = JSON.parse(data);

      });
  
      this.connection.start().then(() => { // to start the server
             console.log('server connected!!!');
         }).catch(err => console.log(err));
  }
signalr angular asp.net-core
1 Answers

You don't need to specify the full url, just the hub you want to connect to... Assuming your hub name is spreadhub you just need:

this.connection  = new HubConnectionBuilder()  
    .withUrl('https://localhost:5001/spreadhub', {  // localhost from **AspNetCore3.1 service**
    skipNegotiation: true,
    transport: signalR.HttpTransportType.WebSockets
    })  
    .build();

On the server, if deployed to azure, don't forget to turn on websockets like:

Configuration

user_105811320
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