Re-init variations cause Fatal Error

I installed the plugin and set it but once I click on re-init variations button the website crash due to fatal error:

Uncaught Error: Call to a member function get_variation() on
string in
/var/www/vhosts/domain.com/httpdocs/wp-content/plugins/wpc-show-single-variations/includes/class-admin.php:187
Stack trace:
#0
/var/www/vhosts/domain.com/httpdocs/wp-includes/class-wp-hook.php(324):
Woosv_Admin->setting_page_content()
#1
/var/www/vhosts/domain.com/httpdocs/wp-includes/class-wp-hook.php(348):
WP_Hook->apply_filters()
#2 /var/www/vhosts/domain.com/httpdocs/wp-includes/plugin.php(517):
WP_Hook->do_action()
#3 /var/www/vhosts/domain.com/httpdocs/wp-admin/admin.php(259):
do_action()
#4 {main}
? thrown