Sys600 license issue going from AX to N4


We are taking over and existing system and upgrading it. We migrated an AX station that had an existing sys600 network and modules on it. We added the N4 version of the jar files into our file structure and then migrated the station from AX to N4 without issue. Got the Jace 8000 commissioned and running, data was coming in on devices on the system 600 network. The following day however, the entire 600 network was down, with the error message Apogee License Expired. Is there a step I am missing in the migration process here? Do we really need to purchase an N4 license for this system 600 network?

Thank you