I have a feeling it will be a long battle.

I'm stuck. For some reason, when I call $session, it refers to the View class. Even though it is a Request class. Notice: Undefined property: View::$session in /private/var/www/localhost/application/views/status/make.php on line 1 Fatal error: Call to a member function get() on a non-object in /private/var/www/localhost/application/views/status/make.php on line 1

The mystery was finally solved.
I forgot to put parentheses () to call a method of a certain class.
When calling a property, you don't need to write ( ), and a method becomes a method only when you write up to ( ).
What a fatal mistake.
It took about half a day to find it. Phew.