_ping_url receives 400 BAD REQUEST response on edge.one.ubuntu.com

ubuntu-sso-client:
  Installed: 0.99.3-0ubuntu1

The following header is sent:
{'Authorization': 'OAuth realm="", oauth_nonce="23820431", oauth_timestamp="1283185861", oauth_consumer_key="hPQWPsH", oauth_signature_method="HMAC-SHA1", oauth_version="1.0", oauth_token="HvLosttPxAsilhGUtnwkZicmHOpZxMOIGNuAhicFrLwcMGKPtu", oauth_signature="pzPox5nh5EOWcAogVRnCw03d2DU%3D"'}

The following is printed to the log:
2010-08-30 19:31:01,145:145.74098587 ubuntu_sso.main Opening the ping url with urllib2.urlopen. Request to: http://edge<email address hidden>
2010-08-30 19:31:02,194:194.617033005 ubuntu_sso.main Problem getting the credentials from the keyring.
Traceback (most recent call last):
  File "/usr/lib/pymodules/python2.6/ubuntu_sso/main.py", line 490, in _login_success_cb
    self._ping_url(app_name, email, creds)
  File "/usr/lib/pymodules/python2.6/ubuntu_sso/main.py", line 526, in _ping_url
    response = urllib2.urlopen(request)
  File "/usr/lib/python2.6/urllib2.py", line 126, in urlopen
    return _opener.open(url, data, timeout)
  File "/usr/lib/python2.6/urllib2.py", line 397, in open
    response = meth(req, response)
  File "/usr/lib/python2.6/urllib2.py", line 510, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.6/urllib2.py", line 429, in error
    result = self._call_chain(*args)
  File "/usr/lib/python2.6/urllib2.py", line 369, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.6/urllib2.py", line 605, in http_error_302
    return self.parent.open(new, timeout=req.timeout)
  File "/usr/lib/python2.6/urllib2.py", line 397, in open
    response = meth(req, response)
  File "/usr/lib/python2.6/urllib2.py", line 510, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.6/urllib2.py", line 435, in error
    return self._call_chain(*args)
  File "/usr/lib/python2.6/urllib2.py", line 369, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.6/urllib2.py", line 518, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
HTTPError: HTTP Error 400: BAD REQUEST

This prevents SSO authorizations from reaching ubuntuone servers, therefore client does not work.