Upgrade from 12.04.5 to 14.01.1 fails to check for new Ubuntu release

[Anton Sukhin]

Dear All,

I am trying to upgrade the following headless system running on Windows
Server 2008 R2.
(dynamic memory allocation, min 2048, max 4096, 2 virtual processors, 1
IDE, 1 network card)

Description:    Ubuntu 12.04.5 LTS
Release:        12.04
Codename:       precise

Linux monster 3.13.0-37-generic #64~precise1-Ubuntu SMP Wed Sep 24
21:37:11 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

Below is the output of the upgrade attempt:

anton at monster:~$ sudo do-release-upgrade
Checking for a new Ubuntu release
Unhandled exception in thread started by <bound method
MetaReleaseCore.download of
<UpdateManager.Core.MetaRelease.MetaReleaseCore object at 0x7f612a24b050>>
Traceback (most recent call last):
  File
"/usr/lib/python2.7/dist-packages/UpdateManager/Core/MetaRelease.py",
line 262, in download
    uri=urllib2.urlopen(req, timeout=20)
  File "/usr/lib/python2.7/urllib2.py", line 126, in urlopen
    return _opener.open(url, data, timeout)
  File "/usr/lib/python2.7/urllib2.py", line 400, in open
    response = self._open(req, data)
  File "/usr/lib/python2.7/urllib2.py", line 418, in _open
    '_open', req)
  File "/usr/lib/python2.7/urllib2.py", line 378, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.7/urllib2.py", line 1207, in http_open
    return self.do_open(httplib.HTTPConnection, req)
  File "/usr/lib/python2.7/urllib2.py", line 1180, in do_open
    r = h.getresponse(buffering=True)
  File "/usr/lib/python2.7/httplib.py", line 1030, in getresponse
    response.begin()
  File "/usr/lib/python2.7/httplib.py", line 407, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python2.7/httplib.py", line 365, in _read_status
    line = self.fp.readline()
  File "/usr/lib/python2.7/socket.py", line 447, in readline
    data = self._sock.recv(self._rbufsize)
socket.error: [Errno 104] Connection reset by peer

When I try:

wget http://changelogs.ubuntu.com/meta-release-lts

all if fine and the file is downloaded.

Any ideas?

Cheers,
Anton