If somebody struggling, then fix for me was to use older ESP8266 board drivers 2.5.0, as later ones were showing errors above.
yet even after uploading the project, I cannot authenticate Spotify.
I do have:
2. I do have a redirect set
3. Key, secret, hostname are set as in guide and no other esp8266 devices in the network.
Yet device is not detected by hostname, only via IP, and even if I Replace URL from hostname to IP and even if webpage says it is authenticated, the device still asks to be authenticated... spend two days on it..
Out of ideas