Backup fails with unknown error (Duplicity backend, builtin backup GUI used)

Output in the Backup window:

Traceback (most recent call last):
  File "/usr/bin/duplicity", line 1411, in <module>
    with_tempdir(main)
  File "/usr/bin/duplicity", line 1404, in with_tempdir
    fn()
  File "/usr/bin/duplicity", line 1280, in main
    sync_archive(decrypt)
  File "/usr/bin/duplicity", line 1080, in sync_archive
    copy_to_local(fn)
  File "/usr/bin/duplicity", line 1021, in copy_to_local
    fileobj = globals.backend.get_fileobj_read(fn)
  File "/usr/lib/python2.7/dist-packages/duplicity/backend.py", line 550, in get_fileobj_read
    self.get(filename, tdp)
  File "/usr/lib/python2.7/dist-packages/duplicity/backend.py", line 323, in iterate
    return fn(*args, **kwargs)
  File "/usr/lib/python2.7/dist-packages/duplicity/backends/u1backend.py", line 201, in get
    answer = auth.request(remote_full)
  File "/usr/lib/python2.7/dist-packages/ubuntuone-couch/ubuntuone/couch/auth.py", line 152, in request
    url, method=http_method, headers=headers, body=request_body)
  File "/usr/lib/python2.7/dist-packages/httplib2/__init__.py", line 1444, in request
    (response, content) = self._request(conn, authority, uri, request_uri, method, body, headers, redirections, cachekey)
  File "/usr/lib/python2.7/dist-packages/httplib2/__init__.py", line 1196, in _request
    (response, content) = self._conn_request(conn, request_uri, method, body, headers)
  File "/usr/lib/python2.7/dist-packages/httplib2/__init__.py", line 1179, in _conn_request
    content = response.read()
  File "/usr/lib/python2.7/httplib.py", line 548, in read
    s = self._safe_read(self.length)
  File "/usr/lib/python2.7/httplib.py", line 647, in _safe_read
    chunk = self.fp.read(min(amt, MAXAMOUNT))
  File "/usr/lib/python2.7/socket.py", line 380, in read
    data = self._sock.recv(left)
  File "/usr/lib/python2.7/ssl.py", line 241, in recv
    return self.read(buflen)
  File "/usr/lib/python2.7/ssl.py", line 160, in read
    return self._sslobj.read(len)
SSLError: The read operation timed out

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: duplicity 0.6.18-0ubuntu3.1
ProcVersionSignature: Ubuntu 3.2.0-48.74-generic 3.2.46
Uname: Linux 3.2.0-48-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.3
Architecture: amd64
Date: Tue Jun 18 10:29:41 2013
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Beta amd64 (20120301)
MarkForUpload: True
SourcePackage: duplicity
UpgradeStatus: No upgrade log present (probably fresh install)