Is this a new setup, or did you have any speakers running previously? Play:1 & 3 are quite old models. Are you running S1 or S2? Adding to existing system or setting up a new one? You’ve not given many clues in your post. 

This an old Set up.has happened more once.usally just restart phone and it works.been unplugging router and sonos several times.getting very frustrated 

Use your router’s DHCP settings page to assign static/reserved IP addresses to all Sonos.

Power down ALL Sonos, reboot router and power up Sonos.

It may not solve your problem but it removes one of the more common problems from the list of possibilities.

Thank you.listening to all

Hello I've git a sonos sound bar plugged in a working .But for dome reason, my sub has disconnected! I've updated app.

I can't find sub .I don't know how to reconnect dub snd doing bar please help.