Airplay not working on iTunes installed on Windows 10 PC

Equipment in use; Windows 10 PC; Apple TV; iTunes; 2 Sonos Era 100 Speakers connected by WiFi to the PC.

When I click on(the AirPlay button)  on the top bar of the iTunes menu screen, I have three options to select from: 1 Computer; 2 Living Room: 3 Snug. (See screenshot below). If I select the first option iTunes plays through the computer's speaker. If I select the third option (Snug) iTunes plays through the Apple Tv which is connected to the same WiFi network. However, if I select the second option (Living Room) iTunes should play through the 2 Sonos speakers which are connected to the same WiFi network. Instead, there is no sound at all. This problem has arisen following an update because iTunes used to play through the Sonos speakers. I do not know which update caused it. If I try and make the connection using my Windows 11 laptop I encounter the same problem. If I make the connection using my iPhone (6) or my iPad music is airplayed to the speakers perfectly as is the case if I use the Sonos app on any device. Does anybody else have this problem of not being able to airplay iTunes music from a PC to WiFi connected speakers or is there a solution available. Apple Help says that it is a Windows or Sonos problem; Windows Help says that it is an Apple or Sonos problem; Sonos Help says that it is an Apple or Windows problem! I am the little piggy in the middle, - can anybody help?