no available devices are found

[td3pro]

Plan

Premium

Country

US

Device

iPhones

Operating System

iOS

My Question or Issue

I'm writing an app that uses "currently-playing" WEB API.  The software works against most accounts, but for some, the return is success with no data.  According to the Spotify doc, "When no available devices are found, the request will return a 200 OK response but with no data populated"

What does "no available devices" mean? How can the valid premium account on the phone be available for this API to work?

Thanks,

T