You can simply reset the network to 2.4 as well as 5GHz after connecting.
This is because your phone must be on the same Wifi frequency as your Duux device to initiate communication. This communication is not much more than the login information for your router. Once your Duux device has the login credentials, it will log onto the network and communication between phone and device is no longer necessary.

Note: The above explanation only applies to Beam, Beam Mini, Blizzard, Whisper Flex (Serial number beginning with 21CF or lower), Bora, Threesixty, Tube and Bright (serial numbers ending in: DXPU06: 0500001 - 0501800 & DXPU07: 0500001 - 0501600)