How to set up Calendars in iCal
- Run the Apple iCal/Calendar application
- In the menu, select iCal/Calendar → Preferences
- go to tab Accounts
- Click on the + button to create a new account
- Choose Add CalDav Account...
- Choose Account Type: Manual
- Type your User Name, Password and Server Address [domain.tld]
- Next you need Verify Certificate
- Choose Show Certificate
- Choose Trust
- Choose Always trust