Not working with Twitter (using Selenium)

[TolstoyDotCom]

I'm trying to load Twitter using Selenium and a Firefox profile that's logged in to Twitter. It works without the proxy, but I need the proxy so I can see their AJAX messages. When I use the proxy, I see that I'm logged in to Twitter, but all I get is a 'something went wrong' message. The proxy does work with Yahoo mail.

Here's an example illustrating the problem: https://github.com/TolstoyDotCom/proxytest