@aaaaaaaaaaaaaab,

The live view of cameras will timeout if your phone is not connected to the same network as your cameras - due to both data and battery limitations. This is limited to the live view of the camera though - your camera will still continue to detect events, wake itself, record activity, and notify you of any events even without the live view open on your phone.

If it is a wired camera, you could explore the cameras RTSP/ONVIF connection will essentially broadcasts the video stream from the camera as a video stream across your network - allowing you to see the stream on other apps or services to record. If you are looking for constant monitoring you will want to look for a camera that supports 24/7 recording, but this is usually limited to wired cameras due to the potential for rapid battery drain