I'm having an issue where I get the 'Spotify login failed' message only when I'm using data. I've checked, and I have data turned on for both Pacemaker and Spotify - does it only work when connected to wifi?
I've been looking into this issue again over the last few days. We use some older technology from Spotify which we then built Pacemaker around. This allows us to do DJ style things such as looping audio, slowing tracks down and beatmatching. Unfortunatly this older technology doesn't appear to work over something called IPV6 which means that when you are connected to the Verizon, Rogers Canada or T-Mobile USA mobile networks (there may be others) unfortunately Spotify login fails.
The only way around this currently is to switch to a WiFi network and try logging in again. The majority of WiFi networks use the older IPV4 standard so this should allow you to login to Spotify and mix with Pacemaker.
We'll need to work with Spotify to migrate to newer technology, but this may take some time.