Fatal error: Uncaught mysqli_sql_exception: Duplicate entry 'AHA' for key 'users.username' in /home/alhass29/public_html/assignment7part5/insert.php:8 Stack trace: #0 /home/alhass29/public_html/assignment7part5/insert.php(8): mysqli_query(Object(mysqli), 'INSERT INTO use...') #1 {main} thrown in /home/alhass29/public_html/assignment7part5/insert.php on line 8