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Fatal error: Uncaught TypeError: mysqli_query(): Argument #1 ($mysql) must be of type mysqli, null given in /home/course/u47/public_html/submissions/submission05/scripts/displayListOfCategories.php:5 Stack trace: #0 /home/course/u47/public_html/submissions/submission05/scripts/displayListOfCategories.php(5): mysqli_query() #1 {main} thrown in /home/course/u47/public_html/submissions/submission05/scripts/displayListOfCategories.php on line 5