React PHP - 1006(Underlying Connection closed)

Question

Periodically - and this time is not absolute, between 3~5 minutes, the connection I make via websocket (with the Ratchet library), returns me the following error(I capture in connection closure):

code(1006) reason(Underlying closed Connection)

From what I read, this error happens on my side (as client), it does not seem to be something that the server I am connecting to, has provoked.

I don’t own ping/pong boards, I don’t know how to implement them in my case, but I don’t believe this is the problem, although I consider..

Code(sample):

$loop      = \React\EventLoop\Factory::create();
$connector = new \Ratchet\Client\Connector($loop);

    $connector("wss://xx.yy/ws")->then(function ($conn) use ($loop, $connector) {

        $send = array(
            "method" => "xxx"
        );

        $conn->send(json_encode($send));

        $conn->on('message', function ($msg) use ($connector, $conn, $send) {

            $arr = json_decode($msg, true);

            if (isset($arr["id"])) {
            faca_algo($arr["s"], $arr["b"], $arr["a"], time(), $arr);
            }

        });

        $conn->on('close', function ($code = null, $reason = null) use ($loop, $connector) {
            $GLOBALS["Functions"]->SaveLog("Conexão Websocket foi fechada, codigo(" . $code . ") razão(" . $reason . ")", "LOG_WARN");
        });

    });

Important: this connection receives thousands of requests per second(around 1~2k), I have no CPU or Memory problem, this process does not lock, the loop is not terminated, only the connection drops with this 1006 error..

Using Centos8, Nginx and Apache.