System Updates are Recommended

Parts of, or all of your system is currently out-of-date.

Please update macOS, your host apps & FxFactory in that order.

You can update both macOS & Final Cut Pro free of charge using System Settings & the App Store on your Mac.
Once completed, you can download & install the latest version of FxFactory.

If your hardware is limited, reference the following pages for supported versions: 
https://support.apple.com/en-us/HT206886
https://fxfactory.com/download/archive/