WWW class Windows Store

Hi! I'm trying to port our iOS / Android app to Windows universal but I'm having troubles with the WWW class I use it with no problem on iOS and Android to connect with the server for user data and getting asset bundles. But for no reason when I build for windows universal all www connection returns host error but the url works if I try it on web browser. I also tried the Unity Networking on some calls but text returns null on build not on editor. Does any one have this problems? I'm on 5.6 Thanks!