ECS to public broker using a WebSocket connection problem

[casdolfo]

I have simple API on AWS ECS (using EC2, ARM64).
I want to connect to the sample broker which is shown as an example in the MQTTnet documentation however I always get a timeout.
All secutity groups and load balancers are set to accept any traffic.

I'm using this sample:

    var mqttFactory = new MqttFactory();
    using (var mqttClient = mqttFactory.CreateMqttClient())
    {
        var mqttClientOptions = new MqttClientOptionsBuilder().WithTcpServer("broker.hivemq.com").Build();
        await mqttClient.ConnectAsync(mqttClientOptions, CancellationToken.None);
        // always timeout
    }

Enabled locally, of course, it works well.

Please give me some advices.