We purchased 1 license, and have installed the key on to 1 website. The IP the license is registered to is the same IP the site is hosted on, however, I now have a prompt at the top of my admin pages, and within the license page stating:
You are using The Events Calendar PRO but your license key is out of installs. Visit the Events Calendar website to manage your installs, upgrade your license, or purchase a new one.
[X]
I have confirmed the license is correct.