Hi @foxleybob
Thanks for our post!
Are you trying to play music stored on your phone? Or use your phone to play the Music Library from a computer/NAS?
If the former, and your phone is an iPhone, you’ll need to use AirPlay. If you’re using an Android device and On This Device in the Sonos app, try rebooting your phone.
If the latter, try removing the source and add it again from the Desktop Sonos app.
If none of this helps, I recommend you get in touch with our technical support team, who have tools at their disposal that will allow them to give you advice specific to your Sonos system and what it reports.
"Common sense is the collection of prejudices acquired by age eighteen." - Albert Einstein