Just what the title says.
A project made with Unity 2019 doesn't include the UnityEngine.Networking module, which Makinom Free needs to work.
The closest thing is the Unity Multiplayer HLAPI package, which I believe is where they moved that.
Also, it just doesn't break Makinom, it breaks everything as it tries to reference some unreferencable thing or something. I don't know, I'm just slightly pissed about that is all.
Steps to reproduce:
1) Make a new project
2) Add Makinom Free
3) Enjoy fresh errors
PS: I don't know if this happens in the Makinom Pro version, too, but I'd assume it might. Just made clear I used Free because that's what I used. Hopefully this'll be fixed soon (Or I'll find out how to call an ORK event directly from code or something, I'm not picky, but Makinom could come in pretty handy anyway)