Don't use 2-Factor-Authentication
The 2-Factor-Authentication has great risks, it's a technology that hackers can intercept them at the other end or in air. iMessages codes and Emails authentications can be intercepted by someone at the other end or in air and take control of your account. Public radio has advised the public not to use these forms of authentications for online activities! A few weeks ago, Simplisafe started using Webapp for customers logging in to their account and using emails to confirm the accounts; since then, it's a nightmare come true! I worry I can't trust the system anymore and the system is in someone else's control. Please remove the Webapp and email authentication process to ensure account security!