Issue Summary

Subscribing to a JSM on-call schedule calendar using “Add to Calendar“ in Outlook fails with the error: "Unable to import calendar. Try again later." This issue occurs when IP Allowlisting is enabled on the instance, even if the user's IP is included in the allowlist.

Steps to Reproduce

1. Navigate to Operations → On-call schedules → Add to Calendar and copy the link.

1. In Outlook, go to Calendar → Add calendar → Subscribe from Web, paste the link, and save.

1. Outlook returns: "Unable to import calendar. Try again later."

Expected Results

Calendar should be added to the Outlook Calendar. 

Actual Results

The below exception is thrown in the xxxxxxx.log file:

Unable to import calendar. Try again later. 

Workaround

One of the workaround would be to use a different calendar such as Apple Calendar or the Google Calendar. 

As a temporary workaround, you can export the calendar and manually add it to the Outlook Calendar.

Note: Since this is a one-time export rather than a subscription, any subsequent changes to the on-call schedule will not automatically reflect in your Outlook Calendar.