This is really a PC setup issue and not something we can directly help with. It will also depend on what OS you are running and what you have done to disable the network on your PC. But using your favourite internet search engine for something like "reset network stack" might give you some clues.
You don't need a connection to the internet when running MCUXpresso IDE. But various operations such as debugging do make use of "localhost" network connections to communicate between various tools components. So you will need an operational network stack.
