Thanks for updating the thread.
Can you please let us know the licence that you are trying to validate? Upon checking the your license manager page I see that in 2018 you purchased X Theme licence but that website is using fairly old version of X Theme and Cornerstone. So probably validation won't go through till the time X Theme and Cornerstone is updated.
In that regards, for now you need to manually update X Theme. Please take a look at following article to manually update. Please scroll down to manual update section. Once you have updated X Theme and Cornerstone, you can proceed to validate the same.