Easy php issues connecting mysql [duplicate]

This question already has an answer here:

• PDO: MySQL server has gone away 8 answers

my connection php:

class ConnexionBDD{

    public function getConnexion(){

        try {
                $cnx= new PDO("mysql:host=localhost;dbname=portfolio",
                "root",
                "",
                    [   
                        PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES 'UTF8'',
                        PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
                        PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC
                    ]);
        }


        catch (Exception $e){

        die("Erreur de connexion à la base de donnée : ". $e->getMessage());
        }

        return $cnx;
    }


}

Error code :

Warning: PDO::__construct(): MySQL server has gone away in C:webPortfolioV_3.5controleurConnexionBDD.php on line 15

Warning: PDO::__construct(): Error while reading greeting packet. PID=6980 in C:webPortfolioV_3.5controleurConnexionBDD.php on line 15

Warning: Uncaught exception 'PDOException' with message 'SQLSTATE[HY000] [2006] MySQL server has gone away' in C:webPortfolioV_3.5controleurConnexionBDD.php:15 Stack trace: #0 C:webPortfolioV_3.5controleurConnexionBDD.php(15): PDO->__construct('mysql:host=loca...', 'root', '', Array) #1 C:webPortfolioV_3.5controleurinsertionBDD.php(10): ConnexionBDD->getConnexion() #2 C:webPortfolioV_3.5controleurContactController.php(15): insertionBDD->createClient('coudoumie', 'morgan', '', '') #3 C:webPortfolioV_3.5index.php(35): ContactController->Contact() #4 {main} thrown in C:webPortfolioV_3.5controleurConnexionBDD.php on line 15

Fatal error: Maximum execution time of 30 seconds exceeded in C:webPortfolioV_3.5controleurConnexionBDD.php on line 15