modem problems

I can not access the settings for my modem - when I use the browser 10.0.0.1 it directs me that this is no longer available and to use the app. however the app does not have an option for advanced settings?

i have the router in bridge mode to a Netgear router. also several of the devices i have connected to the network are no longer getting wifi - i suspect this is because of updates that Xfinity have recently done.