Unable to update EPOW forms

Hi, we have an issue with EPOW – Custom Product Options for WooCommerce. We are not able to modify or add forms (global and item). We can edit but once we hit the update button, nothing happens.

In the log-files we see the following errors :

Uncaught Error: Call to undefined function EPOWAdminvillatheme_sanitize_kses() in /home/672970.cloudwaysapps.com/hjwmebwasa/public_html/wp-content/plugins/epow-custom-product-options-for-woocommerce/admin/form-builder.php:305 CONTEXT: {“error”:{“type”:1,”file”:”/home/672970.cloudwaysapps.com/hjwmebwasa/public_html/wp-content/plugins/epow-custom-product-options-for-woocommerce/admin/form-builder.php”,”line”:305},”backtrace”:[“”,”#0 /home/672970.cloudwaysapps.com/hjwmebwasa/public_html/wp-content/plugins/epow-custom-product-options-for-woocommerce/admin/form-builder.php(281): EPOW\Admin\Form_Builder->save_form()”,”#1 /home/672970.cloudwaysapps.com/hjwmebwasa/public_html/wp-includes/class-wp-hook.php(324): EPOW\Admin\Form_Builder->ajax()”,”#2 /home/672970.cloudwaysapps.com/hjwmebwasa/public_html/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters()”,”#3 /home/672970.cloudwaysapps.com/hjwmebwasa/public_html/wp-includes/plugin.php(517): WP_Hook->do_action()”,”#4 /home/672970.cloudwaysapps.com/hjwmebwasa/public_html/wp-admin/admin-ajax.php(192): do_action()”,”#5 {main}”,”thrown”]}