Steps to reproduce:
1) Use a server and port which redirects to another address (like beta.metabrainz.org:80).
2) Lookup for a audio file
3) See debug logs

Here are some debug logs:

D: 01:36:01 Looking up the metadata for file /home/rahul/Music/01 A Kaleidoscope of Mathematics.mp3 ...
PyQt4.QtCore.QUrl(u'http://beta.musicbrainz.org:80/ws/2/recording?query=tnum:(1) qdur:(154) artist:(james horner) track:(a kaleidoscope of mathematics) tracks:(16) release:(a beautiful mind) isrc:(usumc0110404)&limit=25')
D: 01:36:01 WSREQ: First request to (u'beta.musicbrainz.org', 80)
D: 01:36:02 Received reply for http://beta.musicbrainz.org:80/ws/2/recording?query=tnum:(1) qdur:(154) artist:(james horner) track:(a kaleidoscope of mathematics) tracks:(16) release:(a beautiful mind) isrc:(usumc0110404)&limit=25: HTTP 301 (Moved Permanently)
D: 01:36:02 Redirect to https://beta.musicbrainz.org/ws/2/recording?query=tnum:(1) qdur:(154) artist:(james horner) track:(a kaleidoscope of mathematics) tracks:(16) release:(a beautiful mind) isrc:(usumc0110404)&limit=25 requested
D: 01:36:02 Setting rate limit for beta.musicbrainz.org:443 to 1000
PyQt4.QtCore.QUrl(u'https://beta.musicbrainz.org:443/ws/2/recording?query=tnum:(1) qdur:(154) artist:(james horner) track:(a kaleidoscope of mathematics) tracks:(16) release:(a beautiful mind) isrc:(usumc0110404)&limit=25')
QFSFileEngine::open: No file name specified
D: 01:36:02 WSREQ: First request to ('beta.musicbrainz.org', 443)
E: 01:36:04 Network request error for https://beta.musicbrainz.org:443/ws/2/recording?query=tnum:(1) qdur:(154) artist:(james horner) track:(a kaleidoscope of mathematics) tracks:(16) release:(a beautiful mind) isrc:(usumc0110404)&limit=25: Error downloading https://beta.musicbrainz.org:443/ws/2/recording?query=tnum:(1) qdur:(154) artist:(james horner) track:(a kaleidoscope of mathematics) tracks:(16) release:(a beautiful mind) isrc:(usumc0110404)&limit=25 - server replied: Bad Request (QT code 299, HTTP code 400)
D: 01:36:04 No matching tracks for file '/home/rahul/Music/01 A Kaleidoscope of Mathematics.mp3