Why can't I video call with other people?

[AC Question]

Me and my sister have the same phone and both are from AT&T but when I try to video call it goes back to normal or we can only see ourselves and not each other but we can hear each other. Help!

 

[B. Diddy]

Welcome to Android Central! Are both of you able to access 4G LTE, and are both of your phones capable of VoLTE (Voice over LTE, which is sometimes referred to as Advanced Calling or HD Voice)? Video calling over your phone's network typically requires VoLTE to be activated.