How to fix "Could not install packages due to an EnvironmentError: HTTPSConnectionPool" error?

Question

I'm trying to install jupyterthemes package and getting this error.

Collecting jupyterthemes
  Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProtocolError('Connection aborted.', ConnectionResetError(10054, 'An existing connection was forcibly closed by the remote host', None, 10054, None))': /packages/8a/08/9dee6dfd7f2aad6c30282d55c8f495b4dc1e4747b4e2bdbeb80572ddf312/jupyterthemes-0.20.0-py2.py3-none-any.whl
  Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProtocolError('Connection aborted.', ConnectionResetError(10054, 'An existing connection was forcibly closed by the remote host', None, 10054, None))': /packages/8a/08/9dee6dfd7f2aad6c30282d55c8f495b4dc1e4747b4e2bdbeb80572ddf312/jupyterthemes-0.20.0-py2.py3-none-any.whl
  Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProtocolError('Connection aborted.', ConnectionResetError(10054, 'An existing connection was forcibly closed by the remote host', None, 10054, None))': /packages/8a/08/9dee6dfd7f2aad6c30282d55c8f495b4dc1e4747b4e2bdbeb80572ddf312/jupyterthemes-0.20.0-py2.py3-none-any.whl
  Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProtocolError('Connection aborted.', ConnectionResetError(10054, 'An existing connection was forcibly closed by the remote host', None, 10054, None))': /packages/8a/08/9dee6dfd7f2aad6c30282d55c8f495b4dc1e4747b4e2bdbeb80572ddf312/jupyterthemes-0.20.0-py2.py3-none-any.whl
  Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'ProtocolError('Connection aborted.', ConnectionResetError(10054, 'An existing connection was forcibly closed by the remote host', None, 10054, None))': /packages/8a/08/9dee6dfd7f2aad6c30282d55c8f495b4dc1e4747b4e2bdbeb80572ddf312/jupyterthemes-0.20.0-py2.py3-none-any.whl
Could not install packages due to an EnvironmentError: HTTPSConnectionPool(host='files.pythonhosted.org', port=443): Max retries exceeded with url: /packages/8a/08/9dee6dfd7f2aad6c30282d55c8f495b4dc1e4747b4e2bdbeb80572ddf312/jupyterthemes-0.20.0-py2.py3-none-any.whl (Caused by ProtocolError('Connection aborted.', ConnectionResetError(10054, 'An existing connection was forcibly closed by the remote host', None, 10054, None)))

Answer 1

It looks like you'd need to add trusted hosts.

Check this GitHub thread out.

Something like:

sudo pip install --trusted-host=pypi.python.org --trusted-host=pypi.org --trusted-host=files.pythonhosted.org --upgrade --proxy=127.0.0.1:3128 jupyterthemes

Answer 2

please check if date is set correctly. this error pops up usually when the time and date are different from that of the server.