Windows 10. I tried all solutions from the thread. Even turning off antivirus, playing from different devices, play.spotify.com (where everything works like a charm)... and nothing worked. Only uninstalling, cleaning all related files from my profile folder and clean install solved the issue.
I've given up on Spotify ever doing anything about this. I guess they've found the perfect customer service model. Setup a forum and let the customers figure their own problems out. Cheapest customer service group ever.
I saw murmand's post and decided to look into what was left after I uninstalled Spotify. I uninstalled and then did a search for spotify in windows explorer and two spotify folders popped up but neither had anything in them. They were located in the users\yourname\AppData\Local\Microsoft\WindowsApps folder. I deleted both of them and then reinstalled Spotify.
So far so good. I've been playing without issue for two hours where in the past I couldn't get past 2-3 songs. I looked back in that Apps folder and now there is just one Spotify folder. I hope this is it because the lack of actual company support is beyond frustrating.