Proxy settings have no effect

[My Name]

I am using unity-control-center version 15.04.0+15.04.20150410-0ubuntu1 on an Ubuntu 15.04 fresh install.

I am trying to configure proxy using proxy URL by going from: System Settings -> Network -> Network Proxy and selecting "automatic" for "method". I need to add Proxy URL as http://wpad.stusta.mhn.de/proxy.pac (as mentioned on the website: http://www.studentenwerk-muenchen.de/swh/stusta/anleitungen/kurz-anleitung.pdf (section 4.) ).

However, it is not applying these proxy settings. There is no output in the terminal when selecting "apply systemwide" and only the following line when changing to the network settings:

(unity-control-center:5094): network-cc-panel-WARNING **: Error getting registration info: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.ModemManager was not provided by any .service files