PHP Problem in log file. Help!

I see the following error in server log. You know how I can fix it? Is there a compatibility error with Airi and newest version of WP? I get constantly 500 Errors while building my site with Elementor Pro + Airi Pro, and it’s totally anoying. The support from web hosting told me that the theme is the problem!
Please help!Thanks in advance

Sun Feb 03 08:27:27 2019](tel:2019)] [error] [client 172(tel:172).68.62.76] PHP Warning: call_user_func_array() expects parameter 1 to be a valid callback, class ‘Airi_aThemes_Blog_Skin_3’ does not have a method ‘skin_print_template’ in /home/geokou11/athensdrunktour.com/v2/wp-includes/class-wp-hook.php on line 286(tel:286), referer: athensdrunktourcom/v2/wp-admin/edit.php?post_type=page&ids=624
[Sun Feb 03 08:27:27 2019(tel:2019)] [error] [client 172(tel:172).68.62.76] PHP Warning: call_user_func_array() expects parameter 1 to be a valid callback, class ‘Airi_aThemes_Blog_Skin_4’ does not have a method ‘skin_print_template’ in /home/*****/athensdrunktour.com/v2/wp-includes/class-wp-hook.php on line 286(tel:286), referer: athensdrunktoucom/v2/wp-admin/edit.php?post_type=page&ids=624

Hello, please try to follow this tutorial:

Kind Regards, Roman.