loopforever causes issue when ble gateway is not connected

[nishitmodi2591]

The code works fine when the BLE gateway is on. Whenever the BLE gateway is off it stops working and doesn't even give connection error.

Here is my code:

try {
    $mqttclient = new \Mosquitto\Client;

    $mqttclient->onConnect(function() use ($mqttclient, $gateway_topic)
    {
        $mqttclient->subscribe($gateway_topic, 0);
    });

    $mqttclient->onMessage(function($message) use($mqttclient)
    {
        $this->DataParse($message);
    });

    if(!empty($username) && !empty($password))
    {
        $mqttclient->setCredentials($username, $password);
    }

    $mqttclient->connect($mqtt_server_host, $mqtt_server_port, 60);

    $mqttclient->loopforever();

} catch (Exception $e) {
    writeException($e);
}

Please suggest how it can be resolved.