Warning: Undefined array key "usuario" in C:\xampp\htdocs\R\vistas\header.php on line 9

Warning: Attempt to read property "num_rows" on bool in C:\xampp\htdocs\R\vistas\header.php on line 13

Warning: Undefined array key "usuario" in C:\xampp\htdocs\R\vistas\header.php on line 27

Fatal error: Uncaught TypeError: mysqli_fetch_array(): Argument #1 ($result) must be of type mysqli_result, bool given in C:\xampp\htdocs\R\vistas\header.php:29 Stack trace: #0 C:\xampp\htdocs\R\vistas\header.php(29): mysqli_fetch_array(false) #1 C:\xampp\htdocs\R\vistas\Index.php(3): include_once('C:\\xampp\\htdocs...') #2 {main} thrown in C:\xampp\htdocs\R\vistas\header.php on line 29