Able to see Requests but not Responses

Current Configuration

I am currently trying to use mitmproxy to intercept traffic sent and received by Firefox in Ubuntu 14.
I have added the mitmproxy certificates to Firefox and have configured Firefox to use localhost:8080 (which is where I am running mitmproxy) as the proxy for all protocols. I run mitmproxy with no arguments.


I am able to see the requests generated by Firefox in mitmproxy, but the “response” tab is greyed out when I am inspecting a request even though I know there is data being returned by the server.

Am I missing something from my configuration?