Warning

Warning: call_user_func_array() expects parameter 1 to be a valid callback, class 'WP101_Plugin' does not have a method 'api_key_notset_message' in [removed]/wp-includes/plugin.php on line 406

Seen on a multisite, sub-site admin ?page=wp101&configure=1 with no API key.

https://www.ads-software.com/extend/plugins/wp101/