We have discovered that most “T2” Macs require an Internet connection to authenticate the Catalina installer with Apple.

Managed Software Center runs the macOS upgrader while you are logged out; unfortunately, logging out also disconnects you from MWireless (and MGuest), so the Mac is unable to authenticate with Apple’s servers.

Impacted Mac systems are:

We are working on alternate methods around this issue. In the meantime, you may be able to use one of these methods: