Hook callback definition contains invalid 'callback' method name in 'local_nelcxapi'. Callback method not found.

• line 235 of /lib/classes/hook/manager.php: call to debugging()
• line 189 of /lib/classes/hook/manager.php: call to core\hook\manager->is_callback_valid()
• line 304 of /lib/classes/hook/manager.php: call to core\hook\manager->getListenersForEvent()
• line 988 of /lib/classes/output/core_renderer.php: call to core\hook\manager->dispatch()
• line 2066 of /lib/weblib.php: call to core\output\core_renderer->footer()
• line 2476 of /lib/moodlelib.php: call to notice()
• line 85 of /course/view.php: call to require_login()