DIAGNOSIS This is usually a Wi-Fi interference issue. The Ray only uses a 2.4GHz Wi-Fi band, which is crowded and can get shaky if your router is too far away or there's signal conflict.
FIX First, rule out a simple router glitch. Unplug your router and Ray from power for a full minute, then plug the router back in, wait two minutes for it to fully boot, then plug the Ray back in. If it's stable now, it was a temporary network hiccup. If drops continue, improve the signal: 1) Move the Ray or your router so they have a more direct line of sight, even a few feet can help. 2) Avoid placing the Ray right behind a metal media console or directly next to other electronics like a game console, which can cause interference.
IF THAT DIDN'T WORK Your router might be using the same Wi-Fi channel as a neighbor's, causing constant fights. Log into your router's admin page (check for the address) and look for the wireless channel setting for the 2.4GHz network. Try changing it to channel 1, 6, or 11—these are standard non-overlapping channels.
HEADS UP The Ray doesn't support 5GHz Wi-Fi or a wired Ethernet connection. If your 2.4GHz network is chronically poor in that room, your only Sonos-supported fix is to add a Sonos Boost or a Sonos speaker that can be wired (like a One) to create a dedicated SonosNet network, which is more stable.