[Решено] Help with WP Booking system integration

Background of the issue:
I am trying to integrate the WP Booking System plugin with WooCommerce. My checkout was working correctly before I installed WPML. However, it no longer works after installing the plugin. I am using the WP Booking System plugin (скрытая ссылка) and have a checkout integrated with WooCommerce. Link to a page where the issue can be seen: скрытая ссылка.

Symptoms:
Since installing WPML, my checkout has stopped working, and I am now seeing an error on checkout.

Questions:
Why did my checkout stop working after installing WPML?
How can I resolve the error on checkout?