Handheld

It's a stretch to suggest this, since I am not familiar the CGo4/H920 kit. But it sounds like the phone app may not be compatible with your phone. Some of the other Yuneec models that used phone APPS suffered complete loss of functionality as smart phones evolved beyond the currently available APPS. Sometimes an updated APP was be available. Many resorted to buying an older model phone just to use with the APP.
Apologies if this thought has nothing to do with with CGo4/H920.