rooms missing from app

What kind of missing items? Music/streaming choices, or regular UI elements? S1 or S2? Can you provide a screenshot, and tell us what you’re expecting to see?

2x era300 and sub 4 arc ultra is there

So, it is speakers you’re missing, and from the S2 app? Have you tried a network refresh, by unplugging all Sonos devices from power, then rebooting your router? Wait two minutes after the router comes up before plugging back in your Sonos devices.

Which devices are missing? What router do you have? Can you explain your network to us?

Why did you “reboot” and how did you do it? 
 

Has anything changed in your system ( new router, for example)? 
 

You “still have missing items”: are the missing items the same as were missing before the reboot?