An error occuredThe thing is, I have not modified any of my firewall settings. Spotify aside, there's no problem with any of my other applications that need an internet connection. Browsing works fine, using SSH works as usual, etc.
A firewall may be blocking your Internet connection (error 110). Additionally you could try to change the currently used proxy settings.
Temporarily disabling the firewall did not help either. Anyone else having the same problem?
ChrZZ kindly suggested in the comments that resetting my Spotify password should solved the problem. I visited http://www.spotify.com/en/password-reset/ and followed the instructions, and this solved the problem.
Are you also getting the "firewall may be blocking" error? Does resetting the password solve the problem for you too? Please let me know in the comments below.
In the comments Mr Anonymous suggests that all you need to do is to uncheck the "remember me" checkbox. Did this solve the problem for you?