When activating the license key, the website URL is saved and subsequently used to verify the license validity. Plugins retrieve this URL from the database – specifically from the [prefix]_options table, from the siteurl and home values.
WARNING: If you have set the WordPress site URL via PHP (wp-config.php), you also need to set this URL in the corresponding database table for the licensing system to function correctly.
However, this method of setting the base site URL is rather non-standard, and if you installed the site in the normal way, you don’t need to worry about anything.