Warning: Trying to access array offset on value of type null in D:\WWWRoot\prottech.com\www\product_list.php on line 19

Fatal error: Uncaught TypeError: mysqli_fetch_assoc(): Argument #1 ($result) must be of type mysqli_result, bool given in D:\WWWRoot\prottech.com\www\product_list.php:21
Stack trace:
#0 D:\WWWRoot\prottech.com\www\product_list.php(21): mysqli_fetch_assoc()
#1 {main}
  thrown in D:\WWWRoot\prottech.com\www\product_list.php on line 21