Warning: Undefined variable $mysqli in /customers/9/b/b/chbvl5d7j/webroots/www/php/index.php on line 55

Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, null given in /customers/9/b/b/chbvl5d7j/webroots/www/php/index.php:55
Stack trace:
#0 /customers/9/b/b/chbvl5d7j/webroots/www/php/index.php(55): mysqli_query(NULL, 'SELECT Script F...')
#1 {main}
  thrown in /customers/9/b/b/chbvl5d7j/webroots/www/php/index.php on line 55