Node Red behind a proxy

Hello friends, in my work we have put a raspberry pi with raspbian stretch lite, on which we have mounted mqtt and node-red.
At work we have a proxy squid that does not require authentication.
If I create a flow with the HttpRequest node to access the telegram url that contains a url from outside my organization, this node gives an error:
"11/5/2018 13: 04: 53node: e9b89ab8.f85e98
msg: error
"Error: tunneling socket could not be established, cause = connect EINVAL - Local (" "

I have configured the proxy in the operating system, but I have no way for the HttpRequest to work.
Some help?

Also posted in the slack channel and being answered / clarified there.