After clicking the 'Sign in with MusicBrainz' button (at http://acousticbrainz.org/login/) and entering my MusicBrainz credentials (at https://musicbrainz.org/oauth2/authorize?scope=profile&state=JhctmOxrzStYsegsBEMH&redirect_uri=http%3A%2F%2Facousticbrainz.org%2Flogin%2Fmusicbrainz%2Fpost&response_type=code&client_id=jsnvNZnWlqIMansSkJQGWg), the following message appears:

Error: invalid_request

Mismatched redirect URI