strtolower(): Argument #1 ($string) must be of type string, null given 📋

TypeError
Toggle Vendor Stack Frames
            //$this->viewBuilder()->disableAutoLayout();
            //$this->viewBuilder()->setLayout('yourbelly');
        }
        $this->set('site'$this->site);
        $variant_id $this->variantId(strtolower($this->session()->read('site')));
        $this->set(compact('variant_id'));
    }
Error in: ROOT/src/Controller/OrganizationsController.php, line 73

If you want to customize this error message, create templates/Error/error500.php