We are using 1230 Lightweight AP's with WCS, and a Cisco ACS appliance as the Radius server linked into our active directory. We are using WPA and WPA2 Encryption. PC clients can authenticate without issue, however I have a Client with a Apple MAC Book that cannot seem to authenticate. He is claiming he is getting a certificate expired warning and it will not let him go beyond that point. We are using self signed certificates in ACS that are not registered with an external certificate authority (I have made sure the certificate is not expired) and normally on a PC client just uncheck the verify certificates button. I cannot find any in the Apple MAC wireless configuration to turn off certificate checking. Any recomendations? Also, are the certificates from ACS the only ones used for the encryption of the clients or are certificates in WCS or the Wireless controller or AP's themselves to blame?