Hi,
in the recent git version (as well as in the 2.11 release) the part of the authentication process is missing where one has to enter the URL Spotify redirected to and thus it seems not possible to authenticate the app anymore.
I think it is this issue https://github.com/plamere/spotipy/issues/471
Use http://localhost:8080 or instead of just http://localhost as your redirect url (in both code/envvars and in spotify app settings).
Indeed, it is. With a port it works just fine. I suggest to change the docs accordingly, i.e. to modify
"The URL doesn’t need to be publicly accessible, so you can specify “http://localhost/”."
I've created PR #477 which deals with this issue.
Most helpful comment
I think it is this issue https://github.com/plamere/spotipy/issues/471
Use
http://localhost:8080or instead of justhttp://localhostas your redirect url (in both code/envvars and in spotify app settings).