ValueError: check_hostname requires server_hostname

Question

I was going to install pandas and epanettools on my computer using the code shown below with python 3.8.5 and I received one Error exception.

Code:

pip install epanettools
pip install pandas

Actually, I could install epanettools on my old computer and I bought a new computer and I wanted to do the same thing on my new computer, but it didn't work and the error exception shown below after running the code shown above:

Error: Exception:

ERROR: Exception:
Traceback (most recent call last):
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\cli\base_command.py", line 180, in _main
    status = self.run(options, args)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\cli\req_command.py", line 204, in wrapper
    return func(self, options, args)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\commands\install.py", line 318, in run
    requirement_set = resolver.resolve(
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\resolution\resolvelib\resolver.py", line 127, in resolve
    result = self._result = resolver.resolve(
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 473, in resolve
    state = resolution.resolve(requirements, max_rounds=max_rounds)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 341, in resolve
    name, crit = self._merge_into_criterion(r, parent=None)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\resolvelib\resolvers.py", line 172, in _merge_into_criterion
    if not criterion.candidates:
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\resolvelib\structs.py", line 139, in __bool__
    return bool(self._sequence)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 143, in __bool__
    return any(self)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 129, in <genexpr>
    return (c for c in iterator if id(c) not in self._incompatible_ids)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\resolution\resolvelib\found_candidates.py", line 30, in _iter_built
    for version, func in infos:
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\resolution\resolvelib\factory.py", line 258, in iter_index_candidate_infos
    result = self._finder.find_best_candidate(
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\index\package_finder.py", line 879, in find_best_candidate
    candidates = self.find_all_candidates(project_name)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\index\package_finder.py", line 824, in find_all_candidates
    page_candidates = list(page_candidates_it)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\index\sources.py", line 134, in page_candidates
    yield from self._candidates_from_page(self._link)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\index\package_finder.py", line 783, in process_project_url
    html_page = self._link_collector.fetch_page(project_url)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\index\collector.py", line 512, in fetch_page
    return _get_html_page(location, session=self.session)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\index\collector.py", line 422, in _get_html_page
    resp = _get_html_response(url, session=session)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\index\collector.py", line 120, in _get_html_response
    resp = session.get(
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\requests\sessions.py", line 555, in get
    return self.request('GET', url, **kwargs)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_internal\network\session.py", line 449, in request
    return super().request(method, url, *args, **kwargs)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\requests\sessions.py", line 542, in request
    resp = self.send(prep, **send_kwargs)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\requests\sessions.py", line 655, in send
    r = adapter.send(request, **kwargs)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\cachecontrol\adapter.py", line 53, in send
    resp = super(CacheControlAdapter, self).send(request, **kw)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\requests\adapters.py", line 439, in send
    resp = conn.urlopen(
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\urllib3\connectionpool.py", line 696, in urlopen
    self._prepare_proxy(conn)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\urllib3\connectionpool.py", line 964, in _prepare_proxy
    conn.connect()
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\urllib3\connection.py", line 359, in connect
    conn = self._connect_tls_proxy(hostname, conn)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\urllib3\connection.py", line 500, in _connect_tls_proxy
    return ssl_wrap_socket(
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\urllib3\util\ssl_.py", line 432, in ssl_wrap_socket
    ssl_sock = _ssl_wrap_socket_impl(sock, context, tls_in_tls)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\site-packages\pip\_vendor\urllib3\util\ssl_.py", line 474, in _ssl_wrap_socket_impl
    return ssl_context.wrap_socket(sock)
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\ssl.py", line 500, in wrap_socket
    return self.sslsocket_class._create(
  File "c:\users\ziyuan\appdata\local\programs\python\python38\lib\ssl.py", line 997, in _create
    raise ValueError("check_hostname requires server_hostname")
ValueError: check_hostname requires server_hostname

Could you please tell me how to resolve this error? Appreicate a lot if any advices!

Answer 1

Are you using proxy software, like V2ray, SSR...?

If so, close the software, and try again.

Answer 2

On Linux, the problem can be resolved by replacing https with http in the proxy settings environment variable export https_proxy=http://123.123.123.123:8888 . Note, it is proxy settings for https , but an http address is used.

Answer 3

I fixed the problem.

Go to --> windows setting --> Network& Internet --> Proxy --> Switch Turn on (Use a Proxy server) to Turn Off

Answer 4

So far no one has suggested that the pip version is one of the culprits as well. If your virtual environment is having a recent version of pip (eg 21.3.1), try to download the older version same as the one installed in the main python directory (eg pip version 19.0.3). For Windows, copy it to the venv\Lib\site-packages folder and unzip the contents, then cd into that folder then enter the commands python setup.py install to downgrade the pip version.

Answer 5

SSL Trust Issues:

pip install numpy -i http://pypi.douban.com/simple --trusted-host pypi.douban.com

https://jhooq.com/pip-install-connection-error/

Answer 6

On windows,the problem can be resolved by add 'pypi.org' to the proxy whitelist in the proxy settings