I am having Exchange 2010 CAS/HT/MBX server installed at my test network. OWA is working fine. There is no issue at all but RPC and RPC Over https connection is not being established from Outlook 2007 client. During Outlook Profile configuration, i am providing the NETBios name of CAS server, its asking for authentication. Sometimes its being resolved the actual mailbox server name, sometimes not. But very consistently i am not being able to connect mailbox by RPC/RPC over https from Outlook 2007 client. Its showing "Exchange offline" or "Unable to open default mail folder" etc. error messages though during mailbox setup my actual mailbox server name was properly resolved. I will appreciate the help from anyone.