Hello,
Regarding your query, the license you obtain is a single site subscription. It can be connected to only one site at a time. If you have activated your license key more than one website (e.g. localhost or staging site or child theme site) then you will see Invalid License error. You cannot use the same license on your second website without deactivating it first on the previous setup.
If you’re unable to access the previous setup reset the license, email: info[at]themepalace.com
Also, please go through the following link to resolve the issue.
https://themepalace.com/tutorials/activate-themes-license/
Hope this helps.
If you have further queries, kindly let us know.
Regards.