In order to use Calendar Sync for Jira with Outlook.com, follow the steps below.
In Jira, click your profile icon in the top right-hand corner of the screen. A menu will appear. Click My calendars.
The page shows all the feeds and calendars available to you.
Copy calendar URL to clipboard using the Copy to clipboard button, or directly from the text field.
In Outlook.com Calendar, expand the dropdown for Add calendar and select From internet.
Paste the address from clipboard, type a name for the calendar and click Save. An example URL is shown here; your URL will be much different.
After a short while the calendar will appear under Other Calendars and in the main window.
According to Outlook.com documentation, it may take more than 24 hours until a change in Jira is reflected in Outlook.com. This delay is entirely under control of Outlook; Calendar Sync for Jira provides updated data within 5 minutes.