Plotagon Studio is not compatible with MacOS 10.15 ("Catalina"). If you are an existing Plotagon Studio user (that is, you already have a paid subscription), then please read this blog post for more information and to see the options available to you.
If you are an existing Plotagon Studio user and wish to use Plotagon Studio on a pre-Catalina Operating System (Mojave, High Sierra, etc.), then please contact Plotagon Support.