Warning: Undefined variable $conn in /home/pivhr/public_html/cart.php on line 16

Fatal error: Uncaught TypeError: mysqli_real_escape_string(): Argument #1 ($mysql) must be of type mysqli, null given in /home/pivhr/public_html/cart.php:16 Stack trace: #0 /home/pivhr/public_html/cart.php(16): mysqli_real_escape_string(NULL, '5534c03624a7c50...') #1 {main} thrown in /home/pivhr/public_html/cart.php on line 16