If you install FileBot via the Mac App Store then it will work out-of-the-box. This edition does not require a license key and won't ever ask for one, since the Mac App Store controls everything in this regard.
If you download and manually install FileBot from our website then that is completely unrelated to your Mac App Store purchase. This edition does indeed require a universal license.
Please uninstall all versions of FileBot that you may have installed, and then install FileBot via the Mac App Store exclusively as to avoid confusion:
I bought FileBot from the Mac App Store but it's asking for a license?
I bought FileBot from the Mac App Store but it's asking for a license?
Please read the FAQ and How to Request Help.