I used to have a working Sonos environment in multiple rooms around my house. I have two networks due to the shape of the house - the one provided by my BB supplier, using their router, and the other is an Airport Extreme connected to a powerline adapter, spawning off the main router. See diagram attached.
I changed BB provider and the new supplier gave me a new router to work on the same line, with a different name. To all extents and purposes, there shouldn't be any difference other than the name. The speed is the same.
On the first network (connection to the main router), I have a home cinema setup of a Playbar, Sub, 2 x Play 1 and a Bridge. This used to work before the change. Now, when I turn on the TV, I still get all the sound from the system, the Sonos app fails to pick it up and I can't change the volume etc
On the second network (connection to a wireless router on the end of a powerline adapter) everything works fine. I connect the app on my phone with no issues and I can stream audio from multiple sources to my devices - located in different rooms. I can even see the devices that are supposed to be connected to the main network on the app when I'm on the other wireless device.
I have restarted the main router a number of times, deleted the app and reinstalled it, unplugged all the devices connected to the main router and attempted to set them up again.
I cannot get the app to connect to the devices when connected to the main network.