The Outlook for Mac 2011/2016 desktop applications don't provide the ability to subscribe to an internet calendar, but there is aworkaroundthat may work for you.
You can view your Confluence Team calendar directly in Outlook as you would any other shared calendar using iCal synchronization. This is also known as subscribing to a Confluence calendar.
Subscribe to a Confluence Team Calendar Step-by-Step
One-way synchronization means that you can view, but not update, Team Calendars events in Outlook.
1. Get your Team Calendars URL
Click the Subscribe button near the top of the calendar or choose to the right of the calendar name, then choose Subscribe.
Select iCal from the Calendar app dropdown (don't choose Outlook for one-way sync).
Copy the Calendar URL.
2. Subscribe to the calendar in Outlook Desktop
Choose Calendarat the bottom left of the app.
Choose Open Calendar >From Internetin the ribbon.
Paste the calendar address and choose OK.
3. Subscribe to the calendar in Outlook Office 365
Go to the Calendar in the bottom left of the app.
On the left-hand navigation just above My calendars, choose Import calendar...From web
Paste the calendar address URL in the Link section and give your calendar a name, then choose Import