This issue is similar to this old topic:
I have premium with 6 cameras all connected with great signal and working fine. Network is very stable and reliable. I have the WebViewer running on a dedicated machine to display one of the camera views so I can glance at it throughout the day. This works great, except every few hours the camera view goes black. All of the cameras are all still working when I check from my phone. Refreshing the page doesn’t help, but exiting the camera view and opening it again always brings it back. I have tried multiple laptops desktops and tablets, all do the same thing with no loss of connection. On one laptop I did notice Windows would run low on memory after running nothing but the WebViewer for a long time. This makes me think there is a memory leak causing the problem.
It is very frustrating to have to do this every couple hours throughout the day. And not having a reliable way to monitor the video makes it kind of useless since the motion detection is too sensitive.