Push Proxy server not working

Hello,

I'm trying to test the Android App and install a proxy server, but whatever I do, the push notifications are not getting to the android app.

Installed the apk from:
https://github.com/mattermost/android/releases

Installed the push proxy server from:
https://github.com/mattermost/push-proxy

I have enabled the push notifications and have set the server address.

Error in the log file:

[2016/03/05 17:06:09 CET] [EROR] /api/v1/send_push: code=404 ip=MY_IP