OK, I have resolved this issue in my own setup. I have 4 cameras and they have all, at various times, been very problematic. However, they are now completely stable. I have a Unifi Dream machine as my main router and network consisting of a Ubiquiti US-24-250W Main Switch and Unifi UAP-AC-Lite combined with fixed ethernet ports in my house. I have a couple of small Ubiquitie USW-Flex PoE switches dotted around as well.
In order to get stability I did 2 things:
- I assigned a fixed IP address to each camera
- I tethered each camera to a specific wireless access point
Since I did that the cameras are completely stable and have no issues in dropping off or becoming unresponsive.
After that I toyed about with looking at how I could connect using ethernet PoE for 2 of the cameras. I purchased this splitter: https://www.amazon.co.uk/dp/B073P7J1KR?psc=1&ref=ppx_yo2ov_dt_b_product_details
Plug the RJ45 cable into a PoE switch or ethernet port if you have a main PoE switch and connect the USB. I now have 2 of my cameras working via ethernet rather than wifi. Very pleased with them now!