sonos app doesnt work on my one of my Apple devices 2025

There is a limit, but it is 32!

What is the symptom, is it failing to find the system or not working once found?

Check the iOS Sonos app permissions and ensure Local Network option is enabled on the troublesome controller.

​@bockersjv I know there's a limit to the amount of Sonos devices (speakers) you can have in one system. Are you sure there's also an maximum amount of controllers? 

It is often quoted by the support teams:

each Sonos system can accept up to a maximum of 32 controllers.

But finding that info on the support pages is a challenge.  Can’t see it being an issue though, certainly not in this case

You can find the link below by going to Sonos.com > Click on Support > Type “System” > Scroll down to Sonos System Requirements. You’ll find there are a maximum of 32 units per system.

You won’t find (or at least I haven’t) anything that references the number of devices you can have a controller downloaded onto. I have Sonos App (S2) on two iPhones, two iPads and Android tablet. I could most likely add a 6th device if required.

Logic would say Sonos probably omitted anything about the number of controllers on “X” number of devices in a single household to one system to cause a problem as highly remote. I have five (5) but in reality I only need four (4) as mine is an iOS household. The Android device is only for testing.

We need more information to fully understand your issue. Unless a Moderator picks this up and investigates the number of controllers allowed in a household for one (1) system.

https://support.sonos.com/en-us/article/sonos-system-requirements

A search of the forum confirms the 32 controller limit.

Quote from link:
There is no set limit for Sonos Controllers in one HouseHold, except to say this: "You can have up to 32 controllers controlling 1 Player or 1 controller controlling up to 32 Players."

• The number of controllers is limited in our implementation by the number of UPnP subscriptions that our ZonePlayers will support for a single UPnP service.

Whether that has changed with the new app, I don’t know, but I have up to 7 different controllers for my system, although not all being used at the same time.

But this would mean 32 controllers logged in at the same time.