Are you running wireless? If you are, try temporarily hardwiring a PC to test. Many wireless access points built into 'routers' either disable multicast (which Sooloos relies on for device discovery) or throttles it to the point that enough multicast messages are lost to prevent reliable device discovery. If this is the case, hardwiring, changing a setting in the router (if available) or a new wireless access point are the options.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).