Guest WiFi traditionally doesn’t allow devices to see other devices on the network, such as Sonos requires. The only ‘access’ it provides is a direct connection to the Internet.
Try setting up your Sonos speakers on your regular WiFi.
Damned! Thanks for the hint. Then guests can‘t use my Sonos without getting in my regular wifi. This is not what security recommends.
Yea, unfortunately, it is a small concern. However, if you have AirPlay 2 capable speakers, your guests who have Apple devices can see those, without needing access to the Sonos app itself. But they’d still need to be on your WiFi, so that may not actually be much help.