You’ll be asked to enter the authentication code when logging in to the platform the following times. The code is displayed in your authentication app. It is temporary and valid for a short time. So if you enter the code and it’s invalid, check your app — probably, the code’s already changed.
If you can’t use the authentication app, enter the recovery code instead. Remember that recovery codes are one-time, so regularly update them. Always keep the codes in a safe place not to lose them.