I'm have difficulty setting up Exchange ActiveSync in a single Exchange 2003 setup. The Exchange server is front ended by ISA2006 SE. I have read and used the article "How to Publish Microsoft Exchange Active Sync with ISA Server 2006" by Marc Grote. The error that the mobile device gets is "The security certificate on the server is invalid. Support Code : 0x80072f0d". I have the OWA certificate installed on the Exchange and ISA servers since Sept 2007. OWA has been working fine since that time. I think my problem is related to SPN for HTTP/owa.all-mode.com. Should this be on the Exchange or ISA server? Any help is greatly appreciated. Todd Lemmiksoo Network Administrator All-Mode Communications, Inc. 1725 Dryden Road Freeville, New York 13068 (607) 347-4164 x440 1-877-ALLMODE (toll free) http://www.all-mode.com