I have been implementing an application (angular + .net core) and I am using signalR.

When I am testing the signalR with pc browsers (chrome and firefox) everything works fine. However, when I open my app with my phone, signalR does not work.

I am initializing the hub like this.

this.signalingHub = new signalR.HubConnectionBuilder()
  .withUrl('https://localhost:5142/signaling')
  .build();

await this.signalingHub.start().
  then(() => {//simple logic})
 .catch((error) => {//simple logic});

In catch statement, I do some tricks and I can see that this is the error message

‘Error: Failed to complete negotiation with the server: TypeError: Failed to fetch’

I was researching this issue, and I saw one recommendation tells me this

 this.signalingHub = new signalR.HubConnectionBuilder()
   .withUrl('https://localhost:5142/signaling', {
     skipNegotiation: true,
     transport: signalR.HttpTransportType.WebSockets
   })
   .build();

I tried it and now I am getting this error
“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.”

I was using HTTP. I wasn’t sure if the problem was related to it. I started angular with SSL connection but nothing changed. I am getting same errors.