I have a windows server 2012 configured as a NPS/RADIUS server.
By the way Tim, I got it resolved just now. the problem lies on the configuration i did on the controller. under "AAA policy", the MAC Auth server group i accidentally put it as my "nps server ip" instead of "internal". that's why it didn't work. my bad.
so now, im able to get users authenticated with mac address or if not radius authentication.