WebSocket connection to 'ws://127.0.0.1:10086/' failed:

How to configure the mqtt server?

Steps to reproduce the behavior:
1. Using this version of MQTTnet '4.3.6.1152'.
2. Run this code '....'.
3. See error:'mqtt.min.js:5 WebSocket connection to 'ws://127.0.0.1:10086/' failed: ',' Connection error:Error: WebSocket error'

- Client
` var host = ‘127.0.0.1;
var port = 10086;
var path = ’‘;
var clientID = ’123‘; //clientID
var user = ’admin;
var password = '123456';
var url = host+':'+port+path;

var options = {
clientID:clientID,
username:user,
password:password
};
client = mqtt.connect(url,options);
`

```csharp
`builder.Services.AddHostedService();`

MqttHostService.cs
`
public Task StartAsync(CancellationToken cancellationToken)
{
MqttServerOptionsBuilder optionsBuilder = new MqttServerOptionsBuilder();
optionsBuilder.WithDefaultEndpoint();
optionsBuilder.WithDefaultEndpointPort(10086);

optionsBuilder.WithConnectionBacklog(1000);
//optionsBuilder.AddWebSocketEndpoint("0.0.0.0", 9001);
MqttServerOptions options = optionsBuilder.Build();

MqttService._mqttServer = new MqttFactory().CreateMqttServer(options);

MqttService._mqttServer.ClientConnectedAsync += _mqttServer_ClientConnectedAsync;
MqttService._mqttServer.ClientDisconnectedAsync += _mqttServer_ClientDisconnectedAsync;
MqttService._mqttServer.ApplicationMessageNotConsumedAsync += _mqttServer_ApplicationMessageNotConsumedAsync;

MqttService._mqttServer.ClientSubscribedTopicAsync += _mqttServer_ClientSubscribedTopicAsync;
MqttService._mqttServer.ClientUnsubscribedTopicAsync += _mqttServer_ClientUnsubscribedTopicAsync;
MqttService._mqttServer.StartedAsync += _mqttServer_StartedAsync;
MqttService._mqttServer.StoppedAsync += _mqttServer_StoppedAsync;
MqttService._mqttServer.InterceptingPublishAsync += _mqttServer_InterceptingPublishAsync;
MqttService._mqttServer.ValidatingConnectionAsync += _mqttServer_ValidatingConnectionAsync;

MqttService._mqttServer.StartAsync();
return Task.CompletedTask;
}
`
```

Start with MqttHostService.cs and compare the mqtt.min.js WebSocket URL with the server setup, especially the commented AddWebSocketEndpoint call. Verify which endpoint the server starts on and confirm that a WebSocket client can connect successfully to the configured address and port.

Written by the indexing model from the issue text.