Short codes are country specific. In each country, a short code has a different service running on it, so a service that is supported on 55555 in the U.S. supports a different service in Germany. While overseas, you will not receive short code messages. Account & mobile device information Set up security keys. You need to set up at least two security keys so you can use one of them as a backup in case the other one is lost, damaged, or stolen. You can pair up to six keys with your account. Go to Settings > [ your name ] > Sign-In & Security, then tap Two-Factor Authentication. Tap Security Keys, then tap Add Security Keys and .