How to connect to socket.io by an external client?

android
nodejs

#1

Hello, All !
I’m creating a chat.
Server - default chat on cloud9 (NodeJS)
Client - android application. Uses Socket.IO-client Java

Socket socket = IO.socket("https://chat-ravend.c9users.io");
socket.connect()

no answer

How to connect to the server correctly?

P.S.

protocol HTTP and port:8080 returned an error (server):

unhandled socket.io url

Thank you