ActionController::Live goes down after the second connection from the same host

ActionController::Live goes down after the second connection from the same
host

RubyOnRails 4 + Passenger + Nginx
Tested it with curl:
curl -i http://myapp.com/stream
Rails logs after the one connection:
Started GET "/stream" for xxx.xxx.xxx.xxx at 2013-08-20 16:53:01 +0600
Processing by StreamingController#index as */*
After the second connection:
Started GET "/stream" for xxx.xxx.xxx.xxx at 2013-08-20 16:53:06 +0600
Processing by StreamingController#index as */*
That's it, server is not responding to anybody, and logs are clear.