This is the error from the front end
Fatal error: Uncaught TypeError: array_key_exists(): Argument #2 ($array) must be of type array, bool given in C:\.....\wp-content\plugins\agecheck\agecheck.php:735 Stack trace: #0 C:\.....\wp-includes\class-wp-hook.php(305): agechecked_ui() #1 C:\.....\wp-includes\class-wp-hook.php(327): WP_Hook->apply_filters() #2 C:\.....\wp-includes\plugin.php(470): WP_Hook->do_action() #3 C:\.....\wp-includes\general-template.php(82): do_action() #4 C:\.....\wp-content\themes\twentytwentyone\page.php(25): get_footer() #5 C:\.....\wp-includes\template-loader.php(106): include('...') #6 C:\.....\wp-blog-header.php(19): require_once('...') #7 C:\.....\index.php(17): require('...') #8 {main} thrown in C:\.....\wp-content\plugins\agecheck\agecheck.php on line 735