sandras21 on "[Plugin: MultiSite Clone Duplicator] After I duplicated one site, getting error on the website"

I am using multisite and have been using your duplicator plugin before without problems. Now updated wordpress and then tried to clone one site but after did that following error is displayed on the live website:
Waing: call_user_func_array() expects parameter 1 to be a valid callback, function 'Mytheme_remove_style_child' not found or invalid function name in /yoursite.com/htdocs/wp-includes/plugin.php on line 525.

I`m really not understanding php.. but on that line 525 is following:

call_user_func_array($the_['function'], array_slice($args, 0, (int) $the_['accepted_args']));

Can somebody help how do I get ride of that error? I´m using zerif-lite childtheme

https://wordpress.org/plugins/multisite-clone-duplicator/