Hi there,
The speakers need to be on the same WiFi network as the Roku TVs. If the Roku TVs are just using 5Ghz but aren't on a local wireless network, that could be the culprit. If they are on a local wireless network and still not working, make sure everything is up to date. Ensure the TVs have the latest updates, and you may want to take the speakers into the house to the Roku TV you know is working and ensure they're updated to the latest software as well, which will come from pairing with the Roku TV.
Let us know how it goes!
