Hi Amin,
Thank you for reaching out to us. By default the theme searches for everything including the posts and pages. I checked your setup and I see you’re using incompatible versions of X and Cornerstone. Please make sure to update both to their latest versions to avoid incompatibility issues. You can find the latest version numbers here: (https://theme.co/docs/version-compatibility) Then you can compare them to what’s installed on your site.
If you find anything to be out of date, you can review our update guide.
After doing the updates, always remember to clear all caches (if you are using WP Rocket, WP SuperCache or W3 Total Cache) when updating so that the code from the latest release is always in use. This will help you to avoid any potential errors.
Also if you’re using any plugin for searching, you need to disable it as well to make sure the theme searching is not overridden by any plugin or script.
Let us know how this goes!