Hi! I think, I configured all (on server and client) for RPC over HTTPS correctly. Unfortunately, Outlook 2003 cannot connect to my Exchange Server 2003. It tries to connect over TCP 135 (RCP Port Mapper). I expected that it tries over HTTP/HTTPS connections. I logged this behaviour per Ethereal tool on my Outlook client computer. I have the following network configuration for Exchange Services: INTERNET <> NETSCREEN FIREWALL 1 <> ISA Server 2004 <> NETSCREEN FIREWALL 2 <> INTERNAL NETWORK with Front-End-Excahneg + Back-End-Exchange + Global Catalog. Outlook Webb Access over HTTPS works very well. I have the same Certificate and the same Common Name for RPC connections. I tested https://owa.intra.exchtest.net/rpc successfull (403.2 error). My Outlook client computer has Windows XP with SP2. I uses a proxy from client network, but NO proxy script on Internet Explorer, only proxy ports and address. I think that is a problem from Outlook 2003? Can you give me any tipp please! Thanks Mustafa