Have you recently changed anything on your network? Describe your network for us.

As you have found, Factory Reset, while it might accidentally work around something, a mass Factory Reset rarely cures fundamental issues. As a first step I suggest that you close the SONOS controller App, reboot the players, then restart the controller.

in order to reduce confusion for the human, I’ll give each unit a unique room name. For example, I’d name the left surround speaker “Livingroom-LS”.

​@palobulla, if not done so already, after you reset all your players, you will need to fully reset the Sonos App too.
 

Personally speaking, it’s not usually a good thing to reset all the players, as you do lose the ‘Sonos Household’ too and have to setup everything from ‘scratch’ including the music services, Sonos playlists, favourites etc.

i recently ask internet provider for dynamic ip adress as other devices like somfy needed that but this worked properly. I try to reset my aimash network of 4 routers and will see whats happens, those routers work on 2,4 and 5.1, but this settup worked previously very well

Try the setup on just one router/WiFi AP by temporarily switching off the other three - you will likely need to allow DHCP unless you have all the device MAC addresses reserved in the DHCP reservation table with manually assigned (static) IP addressing in place - you will also need to ensure the WiFi networks 2.4Ghz band is 802.11 b/g/n backward compatible - I suggest using WPA2 AES security mode aswell. If you’re not sure about these things then maybe give Sonos Support a call. Here’s the link to do that…

https://support.sonos.com/s/contact

Moderator Note: Removed Serial Numbers. Modified in accordance with the Community Code of Conduct.

Still looks to me like you’re perhaps attempting to use an App with a (now) non-existent Sonos Household - it might be much easier to give Sonos Support Staff a call.