Please make sure that you have registered the purchase code to your licenses page first.
Register the licenses and then assign it to the domain name or site that you are about to validate. I have check your licenses and I could not find that purchase code. It simply means that the purchase code were not registered into your account yet.
To validate X properly, please do the following:
1] Please login to your account and assign the license. You need to assign the license to your site using this url: https://www.example.com/. You have to make sure that url you just assign is the same as the one you have in your settings, Settings > General > Site Address
2] Go back to X > Overview again, and insert the license again.
And please review the changes that we made on how you are going to validated your X theme because we made a big change in the process. Please check it out here: https://theme.co/apex/forum/t/setup-product-validation/55
Hope this helps.