Yes, i confirmed that the camera is online as i'm able to reboot the camera via tpcamera app. As I still able to control the setting for the camera and trigger reboot device. Once the camera rebooted, then it will connected back again. So, I would like to find out whether having issue on hardware or software itself.

Are you playing live view when you phone is connected to the same Wi-Fi? 

Does it happen when you remotely access the camera?