I hard reset my router and could not re-setup my Invoke from my PC. It told me it couldn't contact a service.
Finally I loaded the Cortana app on an iPad mini. It showed the Invoke and its ip address etc, but I still could not connect.
I then deleted the device in the IOS Cortana app. After that, it allowed me to add a new device (my Invoke) and it was able to connect to the network and complete the setup.