Thank you for writing in, please confirm that your One Page Menu is actually set on the Homepage.
How To Setup One Page Navigation
The other issue that I am seeing is your version of X Theme (5.1.1) is not compatible with the version of your Cornerstone (2.1.7). Please update your X Theme to the latest version (5.2.5)
Remember to clear all caches (plugin, server-side, CDN, and browser’s cache) after updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.
Let us know how it goes,