The POWER COMMAND IP instruction only impacts whether the unit will turn back on via IP after it is turned off. So if you can’t see it at all, that’s not related. Most likely the IP address simply changed and that is a manual-only unit so it requires manual addition (which is best solved via a DHCP Reservation on your router).
In that case, just delete the device from Roomie and add it again using the new IP Address. Make sure to remember to use port 10002 for that device.