If you performed a factory reset of all the speakers, you need to redo the setup process for each speaker in the Sonos S1 app. Do NOT use the Sonos S2 app because your Play:5 (Gen 1) isn’t compatible. If I were you, I would reboot your router before you begin the setup process.

Yep, the dreaded “Factory Reset” dumps all your setup info, playlists, streaming services and more, plus it rarely solves an issue other than a temporary fix that could have been had by a simple reboot with no loss of all your setup work.

I’d do as suggested above and follow the new install instructions to get your Sonos system back in operation. Then I’d add setting static/reserved IP addresses in your router’s DHCP page followed by powering down the Sonos, rebooting the router and powering the Sonos back up. Simple to do and it avoids a class of difficult to find problems.