Notice: Undefined variable: mysqli in C:\xampp\htdocs\VERSION 4.4\modulos a actualizar\FE\iniciar_sesion.php on line 7

Fatal error: Uncaught Error: Call to a member function query() on null in C:\xampp\htdocs\VERSION 4.4\modulos a actualizar\FE\iniciar_sesion.php:7 Stack trace: #0 {main} thrown in C:\xampp\htdocs\VERSION 4.4\modulos a actualizar\FE\iniciar_sesion.php on line 7