在谷歌计算云VM实例上设置Coturn服务器错误

I am trying to setup the coturn server on a google compute cloud VM instance running ubuntu 14.04. I think this is a firewall issue but I have opened the port tcp:3478 and udp:3478 in the firewall settings. No other process is running on the 3478 port. Anyone tried setting this on gcloud? What am I doing wrong.I am trying to setup the coturn server on a goo