- Open Apple Calendar
- In the toolbar, click Calendar, then Preferences
- Click the Accounts tab
- In the accounts pane on the left, click the + button to add an account
- Select Add CalDAV account...
- Select Manual as account type.
- Enter the following information:
Account type: Manual
User Name: Enter the email address that you use when logging on your Webmail.
Password: Enter the password for the same email address.
Server Address: caldav.one.com
Add your address to the "My card" on your Mac
Note: Before you can edit an event you've organized, Apple Calendar needs to recognize you as you. Just add your email address to the "My card" in Contacts on your Mac.
- Open Contacts on your Mac by going to Finder > Applications > Contacts
- From the Contacts menu bar, select Card > Go to My Card (if it's not already highlighted), and click the Edit button.
- Add your email address (the one you use with Webmail) to your "My card."