unable to connect multiple One SL

Hello everybody,

I bought 4 One SL speakers at once. And I installed the latest version of the Sonos app.

all speakers have been paired with the app, and they all have had the latest S2 update.

unfortunately there is a troubleshooting or a bug, because I am unable to have all 4 of the speakers together in the app. 
 

Some more info on my situation: they all are connected over WiFi on the same network.

I tried also linking them all over the wired network. 
 

I see the 4 speakers on my “airplay” mode, like for example if I want to listen to Spotify, I have all 4 of them in the list. And they play all 4 the Spotify music. But unfortunately not all at one.

if I ask Spotify to play more than one speaker at the same time, I neer to select the option of opening a room with the S1 Sonos app. Seems to be the standard Spotify respons.

so when I delete an re-instal the Sonos app, I can click on the infinity button to pair/link and it works properly. For a 4 of them this works.

but if I ask to add another speaker to the app, he keeps on searching, but can’t find any other speakers. Evendough they are all listed as available on my AirPlay/Spotify list.

someone got an idea?

thanks a lot!!