My institution runs a filter that makes less safe sites inaccessible. One site that I can reach just fine using a browser is
https://pypi.python.org/simple/waitress/
and yet if I run pip -vvv install waitress
(the problem occurs with all packages, not just waitress) from an Anaconda command prompt I get:
Could not fetch URL https://pypi.python.org/simple/waitress/:
connection error: HTTPSConnectionPool(host='pypi.python.org', port=443):
Max retries exceeded with url: /simple/waitress/ (Caused by
NewConnectionError('<urllib3.connection.VerifiedHTTPSConnection
object at 0x00000000050FD400>:
Failed to establish a new connection: [WinError 10061]
No connection could be made because the target machine
actively refused it',)) - skipping
I can request to selectively open the necessary URLs, but in this case it appears that port 443 at pypi.python.org
is already open.
Can you explain this puzzle? Why is pip unable to reach a site that a browser (on the same machine) can reach?