If you've booted up NBA 2K and find yourself with a confirmation screen stating, "This NBA 2K Account has expired. To prevent this in the future, make sure to confirm your email address with 2K Sports after creating your NBA 2K Account.", don't worry. Your account is still safe!
This message occurs when the email address associated with the NBA 2K Account you've created wasn't confirmed or verified in time after the account's creation. Typically an email will be sent up to 24 hours after the account's creation containing the verification link. Occasionally this email can end up in other folders than your inbox, such as the Spam or Junk folders, so be sure to check them after creating an NBA 2K Account.
This message will continue to appear until the account is verified, so here are few steps to help get you back into the game:
Go to: https://www.nba2k.com
Click "Sign In" at the top-right of the screen
Select the platform you're playing on
Input the email address or username and password you would use for those services.
Once successfully logged in, this will be considered a new account verification. Please follow the instructions in the verification email that will be sent to your account. Note that it may take up to 48 hours for the email to arrive.
After completing the email verification, restart your console, launch NBA 2K, and you should be able to play without any issues!