Reading the postings from about a year ago, I see this is a common problem, but I do not see any solution being put forward.
Every week I search for tracks to listen to when we have friends in. I scan the tracks on my PC and put them in to a playlist. I then listen via the Logitech Squeezebox Touch and my sound system. Several times in the course of the evening it stops with the message "This Track is Not Available in Your Region". Well it is on my PC or I would not have selected it!!! The problem seems to be getting worse.
I have assumed that it is because on my computer I am listen as a European, but the Squeezbox App probably directs me to a US site, where some of the tracks are not available.
This needs fixing, as it makes you want to give up on legal music if the providers are going to treat you like this. The fact that all of the copyright holders are living in the past is not helpful. What is the concept of a region today anyway!
Does Spotify have a solution to this problem?