by Juan Leyva.
If your site is http://winters/ it means that is located inside a private LAN, VPN or something similar.
For accessing your site via the mobile app you must be connected to the same network your computer is connected to accessing that site
I think it's better if you contact your site administrator providing him this link:
https://docs.moodle.org/27/en/Mobile_app
Cheers, Juan