DO mysql managed database pdo problem

no problem when connect via DBeaver but,

unable to connect from droplet whit pdo (php 7.2),

converted downloaded ca-certificate from crt to pem and tried both crt and pem,

PDO::MYSQL_ATTR_SSL_VERIFY_SERVER_CERT tried both, true and false

same result.

$dsn = ‘mysql:’; $dsn .= ‘host=’ . $this->Host . ‘;’; $dsn .= ‘port=’ . $this->DBPort . ‘;’; if (!empty($this->DBName)) { $dsn .= ‘dbname=’ . $this->DBName . ‘;’; } $dsn .= ‘charset=utf8mb4;’; $this->pdo = new PDO($dsn, $this->DBUser, $this->DBPassword, array( PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true, PDO::MYSQL_ATTR_SSL_CA => ‘/var/www/html/mycert.pem’, PDO::MYSQL_ATTR_SSL_CIPHER => ‘ECDHE-RSA-AES256-SHA384’, PDO::MYSQL_ATTR_SSL_VERIFY_SERVER_CERT => true ) );

Unhandled Exception. SQLSTATE[HY000] [2054] The server requested authentication method unknown to the client

any help?