There are a few of us experiencing a similar issue. Today I started with a clean C7 and added several devices, got stuck on one that wouldn't add and even after trying all the tricks it would not go away. Now I cannot seem to add any more devices either. Getting Network Busy messages everywhere. I am going to wait until the repair tonight then try the power down/reboot thing to see if that helps.
If not then I will likely reset everything and this time before pairing devices again I will include my uzb-7 stick as a 2ndary controller just in case.