The license could be tied to your old UX2. Has it packed up completely? If not, maybe just have it plugged in as a dongle, and use your new one as the interface. Just a thought. Probably best to get in touch with support for clarification though.
Line 6 Monkey hasn't connected to the server for quite some time. Have you tried Line 6 central?
To register your Variax, go here. https://line6.com/account/registergear/
Got the same problem. Can't get Monkey to connect to line 6 and can't log in. Tried 2 windows 10 PCs. Monkey doesn't see my 500 or the USB interface. Says in the
download section that both are supported by 10 and 11. With central the USB interface is recognised and I can log in.