CITES has renewed the SSL certificate for Illinois Chat today (3/1/2011), putting into place a new InCommon COMODO-signed certificate.
If your IM client is displaying an error such as "The certificate for chat.illinois.edu could not be validated," we recommend that you upgrade your client to the latest stable version. Older Pidgin clients for Windows are especially prone to this error. Upgrading Pidgin for Windows will resolve the issue. To download a recent version of Pidgin for Windows, visit http://www.pidgin.im/download/windows/.