I have four Sonos One SL speakers around the house including one in my office. The speaker in my office will play music if I add it to a group with other speakers in the house - ie when its a “follower”. However if I want to play only on that one speaker or I chose that speaker as a “leader”, I get the message “Unable to play because server cannot be found”. Sometimes I try to trick it by starting to play music as part of a group then dropping out the other speakers. After a few seconds the playback stops and the message appears.