Servers for NBA 2K18 will be shut down later this month.
If you are still playing NBA 2K18, you will no longer be able to take it online after January 18.
According to 2K Games, any mode that earns or uses VC will be affected. This includes other online functions such as MyTEAM mode and online matches against other players.
You will still be able to play offline quick games along with MyGM and MyCAREER modes. Doing so will earn you SP instead of VC.
If you created a MyCAREER or MyGM online save file before the servers go offline, data will no longer be available for use and you’ll have to start a new game in those modes.
As TheSixthAxis notes, the server shutdown shouldn't come as a big surprise considering the age of the game. NBA 2K17 was pulled offline at the start of 2019, which means NBA 2K19 will be taken offline around the end of 2020.
NBA 2K20 is the most recent release in the annual franchise.