There isn’t enough information presented in your post to make an educated guess, so an uneducated guess would suggest some sort of interference between the speakers and the Sonos update servers. I can think of at least 3 or 4 reasons, but the easiest remedy might be wiring the PLAY:5 directly to your router with an Ethernet cable. It also might be resolved by a network refresh, by unplugging all Sonos devices from power, and while they are unplugged, rebooting your router. Once the router comes back up, plug the Sonos devices back in to power.

There are more network possibilities, but without more information, it is hard to tell.