Things to test: right click on the camera thumbnail and do "Forget custom settings".
If that doesn't work, go to Help > Open log folder then go in CameraProfiles and IDS and delete the file there.
Did you plug them back in the same USB ports? It's best to use ports that are on different USB root controllers so each can have the full bandwidth and power.
I was able to narrow down the problem. The camera works fine when setting the resolution to the cameras max in IDS then saving it to the camera's parameters.(I delete profiles in between these steps). The errors occur when the camera parameters are set to a lower resolution through IDS then saved to the cameras parameter set.
The issue is now that the camera that previously worked is using the same profile set under IDS is only showing black. I know the profile worked because it was what I used to record the video in the original post. Now I see either black image or kinovea completely crashes.
Im trying to capture golf ball impact, if its any help for you.