The latest ZSight update for iPhone and iPad devices created a bug with the connection to the Zmodo server that is preventing users from creating new accounts and sometimes accessing current ZSight accounts using ZSight.
Until the next iOS ZSight app update is approved by Apple, you can get around this issue by downloading the free mobile app called Meshare.
This Meshare app is the same as the ZSight app in most ways, you can create a new account and login to a current account. To access a current ZSight acount from the Meshare app, simply enter your ZSight login credentials into the Meshare app and login. You will be able to see all devices from the Meshare app that you've already added to your ZSight account using ZSight.