pip install gunicorn - ConnectionTimeOutError

Estoy intentando instalar gunicorn con pip en mi entorno virtual y me sale lo siguiente:

Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connection broken by 'ConnectTimeoutError(<pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0x7fcd73156128>, 'Connection to pypi.python.org timed out. (connect timeout=15)')': /simple/gunicorn/  

No se porque me sale esto, dado que antes no salía este error.
Intenté instalarlo de manera manual desde su archivo fuente y se queda en este proceso:

Collecting git+https://github.com/benoitc/gunicorn.git  
  Cloning https://github.com/benoitc/gunicorn.git to /tmp/pip-xjmlr44m-build  
fatal: unable to access 'https://github.com/benoitc/gunicorn.git/': Failed to connect to github.com port 443: Connection timed out  
  Complete output from command git clone -q https://github.com/benoitc/gunicorn.git /tmp/pip-xjmlr44m-build:  
    
  ----------------------------------------  
Command "git clone -q https://github.com/benoitc/gunicorn.git /tmp/pip-xjmlr44m-build" failed with error code 128 in None  

No se que pueda estar sucediendo, si son permisos de red u otra cosa.