Nighthawk CM1200 Modem installed and now Sonos is not working

I have recently upgraded to a nighthawk CM1200 modem.  My sonos systems keeps telling me that my phone is not on the same network as my sonos system.  I have tried all the troubleshooting steps suggested on the app with zero success.  I have moved and plugged in one of the speakers (a 2nd generation play 5) locally at the modem.  The speaker still is not recognized as being on the system.  I also tried do the same with a 1st generation play 5 speaker connecting locally with the modem and speaker with same unsuccessful results. Is there a way to change the network name and password within the sonos app?    I am operating on iphones, ipads and an imac.   Any help would be appreciated.