Why can't Push Notification work in mobile but only in Wifi?

[aurmol 0]

Does anyone know why my push notification in the dahua gDMSS mobile can only work when it is in Wifi but not in cellular 3G signal? Any specific setting for each signal?

 

How does Push exactly work? When you enable it in your phone. Does it establish continuous contact with your NVR or use a server or something? Please elaborate details how it work. I want to understand why can't it work in mobile but only in Wifi. Thanks.