the current version of the Ubuntu package (Ubuntu 14.04 / crossbar 0.13.2) seems to be unable to accept rawsocket connections. I’m seeing this exact issue, but with AutobahnCpp: https://github.com/crossbario/crossbar/issues/856
Using the current crossbar v16.10.1 works fine, so the underlying issue seems to be resolved.
Could you please update the Ubuntu packages? They are really helpful for an easy, robust setup.