i have configured picard to use my username/password for musicbrainz.
unfortunately, it throws an error at startup (on the cmdline):

> E: 00:08:03 Network request error for https://musicbrainz.org/ws/2/collection: Error downloading
> https://USERNAME:PASSWORD@musicbrainz.org/ws/2/collection - server replied: Bad Request (QT code 299, HTTP code 400)

so i tried accessing https://musicbrainz.org/ws/2/collection from my browser, and it returns 'Authorization required.' even when entering the correct username/password.

my musicbrainz username contains an umlaut (namely 'ü'), which is then escaped to an html-entity ('%C3%BC').
i think that this is the cause for the problem.

btw, logging into the ordinary webservice (not using http basic auth) works as expected.