Hi @GoddessBeginnings,
I have checked your Themeco Account and found that the website listed uses the Pro license, but the issue you are facing is related to the X. It seems that you might have upgraded to the Pro, and still using the X and that is the reason why it shows the license is not valid for X while trying to update.
If you have upgraded your license to Pro, I would suggest you download the latest version of Pro and replace the X. You can go through the process here: https://theme.co/docs/converting-from-x-to-pro.
I also checked the listed website and found the TwentyTwentyOne theme is active and using an older version of Cornerstone i.e. 6.0.8.
If that is not the case or you are referring to any other website that is listed in another account, please mention it for further investigation and also share login credentials for your site in a secure note to examine, including:
– WordPress Site URL & Login URL
– WordPress Admin username/password
To create a secure note, click the key icon underneath any of your posts.
NOTE: The Cornerstone plugin is not required separately for Pro, you can deactivate and delete it.
Thanks