Substream stable, Mainstream no signal

[Cameratime101]

I have been battling "No Signal" screen. It works when it wants but can get a good 3000 signal resets in the log in 1 day. Some times it can stay stable all day until I make a change and then it goes haywire, most of the time no signal. Initially when i installed the camera it had no substream. After a month of playing with settings a substream appeared. So I changed to the substream and it is now working flawless. What could cause the mainstream to play up but not the substream?

Fyi cheap ptz camera comes up as Eyeplus-dev and uses the ycc365plus ui to change settings in the camera.