PDO returning error when no error

Question

Randomly, I get the following error while upgrading my system:

Fatal error: Uncaught PDOException: SQLSTATE[HY000] [2002] Cannot assign requested address

By error, it can not connect to the server, but the server is there, and is on, absolutely sure of that, because in other PC’s when you give this error in mine, in others continues normally.

There is no standard for this to happen, it is for no reason, sometimes when I update my page, or make some request via ajax, PHP returns this error, I do not need to do anything, just update one or two (sometimes much more) that it returns to work normally.

Detail, this occurs more often in my production PC (with Ubuntu 16.4) in my test (Win 7) occurs rarely.

This system is on an internal server (Debian 7), the network has a proxy and firewall, but my development Pcs do not go through either.

I’ve been having this annoying problem for a few days, any suggestion is welcome as I’ve tried everything I could think of.

NOTE: My database is relatively large.

Connection code is as basic as possible:

namespace MySQL;
class MySQLConector {

    /**
     * Receber a conexão
     * @return \PDO
     */
    public static function get_conn() {
        $database_url = '192.168.0.254';
        $database = 'database';
        $database_user = 'user';
        $database_pass = 'password';
        $PDO = new \PDO('mysql:host=' . $database_url . ';dbname=' . $database . '', $database_user, $database_pass);
        $PDO->exec("SET NAMES UTF8");
        //$PDO->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        return $PDO;
    }

}