Fatal Error: Uncaught Error: Call to a member function add_page()

[maldersIO]

[10-Sep-2021 17:43:13 UTC] PHP Fatal error: Uncaught Error: Call to a member function add_page() on null in /srv/htdocs/wp-content/plugins/ac-addon-extra-columns-master/classes/ExtraColumns.php:26 Stack trace: #0 /srv/htdocs/wp-content/plugins/ac-addon-extra-columns-master/ac-addon-extra-columns.php(35): ACA\ExtraColumns\ExtraColumns->register() #1 /wordpress/core/5.8.1/wp-includes/class-wp-hook.php(303): {closure}('') #2 /wordpress/core/5.8.1/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array) #3 /wordpress/core/5.8.1/wp-includes/plugin.php(470): WP_Hook->do_action(Array) #4 /wordpress/core/5.8.1/wp-settings.php(556): do_action('after_setup_the...') #5 /srv/htdocs/wp-config.php(84): require_once('/wordpress/core...') #6 /wordpress/core/5.8.1/wp-load.php(55): require_once('/srv/htdocs/wp-...') #7 /wordpress/core/5.8.1/wp-admin/admin.php(34): require_once('/wordpress/core...') #8 /wordpress/core/5.8.1/wp-admin/index.php(10): require_once('/wordpress/core...') #9 {main} thrown in /srv/htdocs/wp-content/plugins/ac-addon-extra-columns-master/classes/ExtraColumns.php on line 26