Please go through the link below for best practice.http://www.redelijkheid.com/blog/2013/4/2/cisco-ise-change-of-authorization-coa-not-working

if, the ethernet and radio interface is up kindly check if the band is selected means a,b,g & n.

Please go through the link below on the page no. 370http://www.cisco.com/c/en/us/td/docs/security/ise/1-2/user_guide/ise_user_guide.pdf

please find the link below may help you.http://www.cisco.com/en/US/docs/security/ise/1.2/user_guide/ise_guest_pol.html#wp1554378

please go through the link below may help you http://www.cisco.com/c/en/us/support/docs/wireless/4400-series-wireless-lan-controllers/99948-lap-notjoin-wlc-tshoot.html