I seem to have the same problem. I see you found a solution online, but any reasons as to why it works?
UPDATE: I think I figured out the issue (I'm assuming @Bence_Voros was also setting up octo on a non raspberry pi computer). If you're not using a pi you need to change the username
pi to whatever your username is in the
/etc/default/octoprint (there should be two places you need to change it)