Digium D50 - JS app NetRequest not working?

Hello! I’m extremelly need help about using NetRequest class for Javascript application for Digium D50 (firmware 2.0+). Whatever I do, it returns ALWAYS “request error: 500”. And in the same time if I use this function from PC (Chrome), everything is ok.

So I’m trying to use:

var request = new NetRequest();
request.open('GET', '', true);

Nothing special. Im listening 81 port and see any requests (even on unexists sources). But IP Phone just does not make any request. Please help, it’s very important.