Api with node js - Node.js

I made an easy API using node js and its work correctly on localhost. For my request "http://localhost:3012/data" I have some data. But when I'm trying to host it in my site I have "Page Not Found". (for request "http://mysite:3012/data")

I have never work with sites before that why I have no idea what the problem! I hope you can help me.

thanks!