Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, PDO given in /volume2/web/arduino.hennus.eu/index.php on line 7

TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, PDO given in /volume2/web/arduino.hennus.eu/index.php on line 7

Call Stack:
    0.0000     359408   1. {main}() /volume2/web/arduino.hennus.eu/index.php:0
    0.0004     401664   2. mysqli_query($mysql = class PDO {  }, $query = 'SELECT * FROM `Arsdorf` ORDER BY `timeStamp` DESC') /volume2/web/arduino.hennus.eu/index.php:7