Kodi 16 doesn't handle URL forwarding. If you were using ver 15, you need to change your server URL Address.
If the server is 3.iptvprivateserver.tv then you would use portal3.iptvprivateserver.tv/stalker_portal/c/index.html
If the server is 4.iptvprivateserver.tv then you would use portal4.iptvprivateserver.tv/stalker_portal/c/index.html
If the server is 5.iptvprivateserver.tv then you would use portal5.iptvprivateserver.tv/stalker_portal/c/index.html
etc
And definitely Go to system settings/TV/ General tab and Disable, then Clear your Data, do an IPTV Reset at Papiao site, then Re-enable TV.
/kens