Hello,
Try to disable all the third-party plugins, that do not come bundled with XStore https://xstore.helpscoutdocs.com/article/36-included-plugins , clear all cache, and check then. Maybe one of the additional plugins is a reason for the problem. If it is true, enable plugins one by one to find out which one support you need to contact.
Let us know if any further assistance is needed from our side.
Regards