Hi Ton,
Sorry about the delay in seeing this. I'm not a member of the Support Department, but I did just come across your posts. Please be aware that this forum is intended for user-to-user interaction. While we do have many active employees here in the Community, we, unfortunately, can't get to every thread. For a guaranteed review of a technical issue, we recommend submitting a ticket to the Support Department.
That said, I did have my team review the CalDAV functionality, and it appears to be working as intended. I'd like to get you in touch with Support through an Email or Phone Ticket so they can determine what's preventing the events from syncing. (Please keep in mind that if your issue is found to be caused by a bug in the software, your ticket cost will be refunded back to you.)
I've sent you a quote for purchasing an Email Ticket for a review with the Support Department. Please let me know if you would like assistance submitting this ticket on the Tickets tab of the Portal.
Andrea Free
SmarterTools Inc.
877-357-6278
www.smartertools.com