Error, when I cliking the cup icon

Hi everybody!

I have a bother problem. When I editing a post and I clicking to the cup, the plugin the next error massages display:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'ot_after_theme_options_save' not found or invalid function name in /html/wp-includes/plugin.php on line 470
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'ot_default_settings' not found or invalid function name in /html/wp-includes/plugin.php on line 470
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'ot_add_xml_to_upload_filetypes' not found or invalid function name in /html/wp-includes/plugin.php on line 470
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'ot_import' not found or invalid function name in /html/wp-includes/plugin.php on line 470
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'ot_export' not found or invalid function name in /html/wp-includes/plugin.php on line 470
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'ot_save_settings' not found or invalid function name in /html/wp-includes/plugin.php on line 470
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'ot_modify_layouts' not found or invalid function name in /html/wp-includes/plugin.php on line 470
Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'ot_create_media_post' not found or invalid function name in /html/wp-includes/plugin.php on line 470
Fatal error: Call to undefined function ot_register_meta_box() in /html/wp-content/themes/hueman/functions/meta-boxes.php on line 269

Have anybody meet this problem? Does anyone know the answer?

https://www.ads-software.com/plugins/leaguemanager/