Make sure the phone is on your Wi-Fi network. The phone will search for a Wi-Fi network for ten seconds, which should be
sufficient in most circumstances. If not, start the app again.
Phonos Error Message: Failed to find any Sonos Players
Make sure the phone is on your Wi-Fi network. If you have a complex network you may need to enter the IP
address of one of the Players so the app can find the rest, see here for details.
Takes ages to scan network
If it takes way too long to find anything (long enough for the screensaver to kick in) then your phone probably needs a reboot:
hold power down until you are asked to slide the screen, then once it is off power it on again and you should be fine.