Proxy does not work

[CIAvash]

I set the proxy using the HTTP_PROXY environment variable, and depending on the website's protocol, HTTP::UserAgent does two things:

• http://httpbin.org/ip: it says "Invalid header received from client."
• https://httpbin.org/ip: it just hangs. Probably here.

[CIAvash]

I should add that the host of htttp_proxy is 127.0.0.1. It seems it gives an error if I use localhost.