Call_user_func_array () error and notification of new posts

On my wordpress dashboard, I have always this warnig:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, class ‘VCExtendAddonCustomLayoutClass’ does not have a method ‘showVcVersionNotice’ in /home/username/public_html/wp-includes/plugin.php on line 496

I don’t know the code, what can I do?

Another thing is the subscribers cannot receive the notification of new posts. I use subscribe form. What’s the problem? (I just installed subscribe2 too.)

Thank you very much and hapy New Year.

My site: https://www.micromoneymaker.com