I have several sonos speakers (2 play1s set up as a pair, 2 Play5 gen 1 also set up as a pair and a connect amp). They are all directly connected to my network via ethernet cable (had a lot of problems with wi-fi dropping out). Since connecting ethernet cable directly, I had very few problems (for more then 1 year) but recently, I find that the play5 pair drops out of the group. Sometimes the controller even stops recognizing it, and the controller app prompts me to reconnect it.
Do you think a 'factory reset' will help? I have seen the warnings that data could be lost, but I do not have any data loaded on the speaker, and only use the system to playback spotify from the controller app.