GutHub Connection Error

[sridhar]

When i tried to list my Repo in Organization Github , I'm getting authentication error.

from github import Github
g = Github("<Access Token>")
repo = g.get_user().get_repo("sample")
a = repo.get_contents("demo.txt")
print(a.text)

Error:

Error:
File "C:\Program Files (x86)\Python 3.5\lib\site-packages\urllib3\connectionpool.py", line 594, in urlopen
    self._prepare_proxy(conn)
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\urllib3\connectionpool.py", line 805, in _prepare_proxy
   conn.connect()
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\urllib3\connection.py", line 308, in connect
    self._tunnel()
  File "C:\Program Files (x86)\Python 3.5\lib\http\client.py", line 832, in _tunnel
    message.strip()))
OSError: Tunnel connection failed: 407 AuthenticationRequired

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\requests\adapters.py", line 449, in send
    timeout=timeout
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\urllib3\connectionpool.py", line 638, in urlopen
    _stacktrace=sys.exc_info()[2])
  File "C:\Program Files (x86)\Python 3.5\lib\site-packages\urllib3\util\retry.py", line 398, in increment
    raise MaxRetryError(_pool, url, error or ResponseError(cause))
urllib3.exceptions.MaxRetryError: HTTPSConnectionPool(host='api.github.com', port=443): Max retries exceeded with url: /user (Caused by ProxyError('Cannot connect to proxy.', OSError('Tunnel connection failed: 407 AuthenticationRequired',)))

Could anyone help me out on this ?