When asked for a 2FA code during log-in, you have the option to use your one-time backup code. This code can be found at the last step of the 2FA activation process, or in the Two-factor authentication section found in the Settings Menu.
Make sure you back it up and keep it in a safe and easily accessible place.
How to log in with your backup code:
Log in with your credentials, then tap on the LOST ACCESS TO 2FA CODES? button on the bottom side of the screen.
After you've tapped on the button, a window will appear from the bottom of the screen. Tap on USE BACKUP CODE.
Enter your code, and tap CONTINUE.
Then write down your new code, and you've successfully logged in using your backup code.