You should:
- Make sure the user is being assigned the role that has the rules
- Configure your ACLs with logging to ensure that when the rule is hit, it is logged
Check what category the URL is in by browsing to http://www.brightcloud.com/tools/url-ip-lookup.php and entering the URL.
Every IAP besides the IAP-92/93 should provide web filtering support in Instant OS 4.1 and above.
Type "show dpi stats webcategory" to get detailed information about what is being filtered on that IAP.