Have you tried restarting your phone or resetting the app?

Yes done that. Took everything of and stated from scratch twice 

It used to work with my surround system. Till I updated the app

When you updated the app, did the Beam also do a firmware update?

Were you using the S1 app before or did you have the S2 app and recently updated?

Are you able to hardwire the Beam to your router to see if it shows up in the app?

Can you describe your network?

Can you describe your Sonos system?

Not sure if the beam dud a firmware update. 

I changed my router from an EE to a BT router

I been on the S2 app for a while now.

Unabke to hardwire to to router.

Network is ee / bt

Sonos system. I have alexa s1 that shows on the app. Also 2 s1 sonos speakers that show on the app.

I just have problems with the beam. As I cant use the surround

Try moving the beam closer to your router so that you can connect them temporarily. The beam should show up in the app and then you can check for updates and apply them. Set up your beam while still connected. Once it is setup, you can disconnect it from the router and move it back to its original location.

If it is a pain to move the Beam, Amazon and others sell cheap 50 and 100 foot ethernet cables.

Pretty, spouse approved colors are also inexpensive, even if you only need it a few minutes.

Ok so I got the app up and running when I connected to the router. But as soon as I took it of and rebooted the app it wasn't there

So, hook it back up with the Ethernet cable so it shows up. Make sure the WiFi/radio on it hasn’t been turned off, the correct network information is in your Sonos controller, and the network conforms to the Sonos Network Requirements FAQ. Check for wifi interference , Then, if none of that makes a difference, submit a system diagnostic within 10 minutes of recreating this ‘error’, and call Sonos Support to discuss it. But don’t post the resulting diagnostic number here, they get sensitive about GDPR.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.

When you speak directly to the Support staff, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.