This plugins counts the license against the home URL. Since WPML changes your home URL based on the language, your license becomes invalid. You will get more information from FAQ.

I’m working on a solution to exclude the language URLs. Next update will have this solution, ETA next week.

Until then can you add the language URLs to your allowed sites list through the purchase history. Once you update the plugin, you can remove it freeing up your licenses.

Thanks

Syam