My Amncrest 6mp cameras are not wireless..they are POE.

Fair enough. I'd still look at the camera logs to see if they're logging any errors - it would reveal a clue. And if there's nothing in the logs, I'd be satisfied that it isn't the camera settings.

Try to remove or change RAM modules, may be is a hardware problem.

There's a Troubleshooting Toolkit that addresses troubleshooting Cameras

Just started having this on many cameras after being stable for several years. Opening camera settings and then just clicking ok without making any changes restores each camera. The troubleshooting page points at hardware acceleration, so I've just set that to "none" on all cameras. Here's hoping....

Yes, it's a good one to turn off as part of testing. I also noted in my experimentations that hardware acceleration had little effect if you are using sub-streams.

Anything in the Logs ?

I haven't dug into the logs, but all the cameras have been stable for over a week. Calling it fixed.

Good enough for me