Are you Android or Apple?

Uninstall the app. Reinstall the app and connect to your system again.

Some iOS users have complained about the same issue, and uninstall/reinstall worked for them.

Happening to me on an older Android, couple newer ones have no issues.

For a few days a device reboot fixed it but that didn’t work this time.

Haven’t tried seeing if the background process is still active and killing it, so when I get around to it I’ll do that before I try the remove and reinstall.

Edit, just tried the kill option and it failed to let it start without stopping.

@jonwhsjes 

Before reinstalling make sure to restart your smartphone. 
But first of all I also recommend a complete restart of your system including all Sonos and network devices (router, switches, wifi extenders). 

I have the same problem. I’m so tired of all this crap with Sonos. Can’t load the app, can’t play music. What’s the point in even keeping this junk.

If you removed, rebooted, reinstalled then you should call Sonos Support and have them look at the problem. They have more tools than we users do and if nothing eles you’ll get your problem on the bug list.

I have found a way that it works, shouldnt have to do it, but it does work. What you should do is disconnect your Wi-Fi from your phone and open up the Sonos app then load your Wi-Fi and it should load just fine. 

Since sonos supposedly “upgraded” their system it hasn’t worked for us and now I can neither open the app or delete it from my iPhone! The sonos app button opens to a black screen and stalls for a while before zapping it closed. Sigh. 
 

Sonos doesn’t respond to emails. 
 

Any thoughts? Will try the suggestion to turn off WiFi and then open. But overall Sonos is a truly sad state of affairs. 

@DiannaL1

What phone and what os? Android? Apple iOS?

If you „can’t“ delete the app from your phone, imo there is something wrong with your phone. 
Please try to restart the device, delete Sonos app, do a restart again and reinstall Sonos app from appstore or playstore. 

And while they don’t really respond to emails for support, they do respond to phone calls. You may want to call Sonos Support directly to discuss it.

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

@DiannaL1 You should be able to at least delete the app to install it again. Why can’t you achieve this?