Fatal error: Uncaught mysqli_sql_exception: Table 'user' is read only

Question

I'm creating a register (sign up) page but when I want to execute the insert command this error message appears:

Fatal error: Uncaught mysqli_sql_exception: Table 'user' is read only in C:\xampp\htdocs\pfa\login.php:12 Stack trace: #0 C:\xampp\htdocs\pfa\login.php(12): mysqli_query(Object(mysqli), 'INSERT INTO use...') #1 {main} thrown in C:\xampp\htdocs\pfa\login.php on line 12

This is the PHP code:

I changed the privilege of all users (including "root" and gave them ALL PRIVILEGES but still the same problem: table user is on read only