gistfile1.txt

$ env | grep HTTP
HTTP_CLIENT=curl --insecure -f -L -o

$ lein version
Downloading Leiningen to /Users/alex/.lein/self-installs/leiningen-2.4.0-SNAPSHOT-standalone.jar now...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (22) The requested URL returned error: 403
Failed to download https://leiningen.s3.amazonaws.com/downloads/leiningen-2.4.0-SNAPSHOT-standalone.jar
It's possible your HTTP client's certificate store does not have the
correct certificate authority needed. This is often caused by an
out-of-date version of libssl. Either upgrade it or set HTTP_CLIENT
to turn off certificate checks:
  export HTTP_CLIENT="wget --no-check-certificate -O" # or
  export HTTP_CLIENT="curl --insecure -f -L -o"
It's also possible that you're behind a firewall haven't yet
set HTTP_PROXY and HTTPS_PROXY.