Can you answer a few questions first?

1. What app are you using? Should be the S1 app only for gen 1 Play 5s
2. Do you have any S2 compatible speakers in your home?
3. Did you have them powered off for a long time? If so, give Sonos Support a call.
4. Have you made any changes to your network? If so, you may need to factory reset both of them
5. Have you tried connecting one of them to your network with an Ethernet cable? Sometimes this may solve your issue.

You don’t list it in your profile, but if you have a Bridge power it down and move the Ethernet cable to one of the Play 5s to see if they connect. The Bridge is old and often a cause of connection issues.