Camera's will not pair to the hub while the hub is connected via WiFi. You have to plug the hub into an ethernet cable for the camera's to pair to the hub.
This is not expected behavior. As long as the hub and cameras are together on the same LAN and upnp is enabled on your router, they will pair - it doesn't matter if the hub is connected via Wi-Fi or ethernet. If you are having any issues with this, please call support for assistance
I was able to get them all paired with the hub plugged into ethernet. Also the cameras stop working after about 30 minutes while the hub is on WiFi and I have to plug the hub back into ethernet for the cameras to start working again. It's almost like everything works fine on WiFi and the hub except the camera pairing (haven't tried recently) and camera operation. I have just left mine on Ethernet for now. Also the hub won't connect back to Iris via WiFi if the hub is rebooted while on WiFi, not sure if this has something to do with it. I have to plug the ethernet back in for it to connect to Iris and the WiFi to start working again, almost like it has to download it's WiFi settings again.