FIlebeat httpjson support for proxy connection

I am attempting to configure filebeat 7.9.2 (running from docker image) to use the httpjson input. It works fine with an internally available URL but times outs on an external URL. I have verified and tried multiple combinations of the environment variables https_proxy and http_proxy. Upper and lower case including using a value that should return an immediate unathenticated error code.

Anyone have experience with this? Is this a known issue?