Hello. On one of the devices. Remove it from your account in the app. Reset it through the physical button. Repair it and test.
With the other in the app flip off then on IR when it’s dark and test.
If that fails it could either be the amount of power supplied to the camera - are you using the adapter and cable that came with the cameras and not via a USB extension?
If all else fails they may just be faulty - but two out of three seems strange. But if they are instigate a return with your retailer