Hello @Gnosis123,
Thanks for writing to us.
As per your given error, it might be the issue in the child theme, I would suggest you please deactivate the child theme and activate the parent X theme and then check it again. Please note that we don’t provide customized child theme support, it is out of the support scope. I would suggest you please contact a developer who can assist you with your concerns or you may subscribe to One where customization questions are answered.
Alternatively, you can downgrade your theme to the stable version, or you can download the previous version of the theme from the Themeco account dashboard.

Thanks