ASUS router by any chance? I know you’ve said that just one cam is misbehaving, but if so it wouldn’t hurt to reference the following post. After disabling this setting on my ASUS RT-1900, all 3 of my cams began connecting much more reliably. My $0.02 …
How to check Asus Routers - Disable “Airtime Fairness”
I did this thanks to another post on here, and now my cameras work like a charm. You can always reset your router back if it doesn’t work.
Thanks milehiguy