Factory default reset...now showing "Video Loss" on all camera feeds

Did you try taking the camera cables out of the nvr and replugging them in?
 
Give Nelly a call. They're great and will get you back up to speed. I'm curious to hear what the problem is. Sounds like the poe ports are looking for old addresses before you defaulted. Or it could be a setting where you don't have the channels assigned or enabled. Nelly will help you. Good luck.
 
If you can navigate to the cameras menu you might try setting them to dhc instead of static address so the nvr can reassign the cameras an address.