I am able to connect Outlook 2007 to a WSS 3.0 calendar on our intranet site (same domain). Even though the dialog specifies 'Read' permissions, I am able to create or change an appointment in either Outlook or SharePoint and have the other party synchronize within a minute or so.
I am trying to connect to a second WSS 3.0 calendar which I can access via the internet (hosted by Small Business Server 2008 using SSL). I get the same setup experience (Permissions: Read) but any attempts to create or change an appointment from Outlook fail with a error message stating that I only have read permissions.
Why does it work in one scenario, and not the other? Is there a specific configuration setting that I need to apply to the SBS 2008 site? Or is a domain membership required for this feature to work (this seems to be the only difference between the 2 cases)?
Is your account a "Site Owner" or "Farm Administrator" on the first site but not the second? Also, what are your permissions on the Calendar list?
From: http://social.technet.microsoft.com/Forums/en-US/sharepointadmin/thread/c2beb41e-df8b-4c3c-af7c-454421ed38c0
I had the exact some issue and worked around it by disabling the server certificate revocation check in IE and restarting Outlook. It makes sense to me, since we are using a server certificate issued by an CA that is only available on the internal LAN, to identify the server publicly. Therefore, clients on the LAN can reach the CA and obtain revocation info, while external clients cannot.
By following the instructions (turning off server revocation checking) I was able to import SharePoint calendars and task lists with write permissions.