Hello There,
Thanks for writing in! Before validating your X theme, please login to your account and assign the license to your site. You can then use the license code in your WP dashboard, X Addons > Home (http://prntscr.com/apmw2m). To know more about how you can validate your X theme, please check out our knowledge base here: https://community.theme.co/kb/product-validation/
Hope this helps.