The two-factor authentication, also called 2FA, is an additional level of security for your Nuri account. 2FA adds a further verification step to the login process and is therefore strongly recommended, but not necessary for registration. If you haven't activated it, you can log in without 2FA.
To use the 2FA, you need the authenticator app, which you can download from the Appstore or Playstore. After linking, you will receive a securely generated six- to eight-digit code on your smartphone, which you enter when logging into your Nuri account after your login data and your password. This means that access is only possible with all three components.
Activating 2FA on online accounts, including personal email accounts, is highly recommended, as 2FA makes data much more difficult for hackers to access. The 2FA process is considered to be the best security measure for your own privacy and security.