CSN mismatch happens when a license with another CSN is activated on the server or client and when another license with a different CSN is activated, it throws an error.
Due to the complexity issue, there isn't much you can do and only a couple options to move forward. Uninstalling will not fix the issue.
Two options are:
Contact GE Digital support directly, have activation codes, CSN and Device ID ready to unlock them.
Activate licenses on a different machine ( If using a Local License Server) and have the clients go connect to it.