Issue Summary

Since Confluence 9.2, when a Confluence administrator disables and re-enables Private URLs in Team Calendars, new Calendar subscriptions are getting denied in external calendar clients such as MS Outlook desktop app and the Apple Calendar desktop app.

Environment:

• Confluence 9.2+
• Apple Calendar app, and Outlook Calendar app in Windows. 

Steps to Reproduce

1. Create a Team Calendar with a few events
2. Browse to General Configuration > Team Calendars.
3. On Security, check "Disable Private URLs" option and click Save.
4. Browse again to Calendars, and generate a subscription URL for your Calendar, under (...) > Subscribe
5. In the "Subscribe to Calendar" prompt, choose "Microsoft Outlook (browser)" as Calendar App
6. Copy the generated link.
7. In your Calendar app, click on File > New Calendar Subscription with this URL. You will be asked username/password to complete the subscription successfully.
8. Now, browse back to General Configuration > Team Calendars; uncheck "Disable Private URLs" option and click Save.
9. Browse again to Calendars, and generate a new subscription URL for the same Calendar as before, choosing "Microsoft Outlook (browser)" as Calendar App

Expected Results

End users can successfully subscribe to the new subscription URL

Actual Results

The end users will receive a "Access is Denied" message when using the new subscription URL.

 
Reviewing the Confluence access logs, you can see that the Calendar app sets a JSESSIONID when communicating with Confluence. Hence, this request gets denied with a 401 Unauthorized response due to an invalid session attached to the subscription request: 

xxx.50.0.2 - [09/Jun/2025:08:59:58 +0000] "GET /confluence/rest/calendar-services/1.0/calendar/export/subcalendar/private/8ce6244a879edf1f5be6aa2e654978d833083020.ics HTTP/1.1" 401 770 10 /confluence/rest/calendar-services/1.0/calendar/export/subcalendar/private/8ce6244a879edf1f5be6aa2e654978d833083020.ics http-nio-8090-exec-4 "macOS/15.5 (24F74) dataaccessd/1.0"    xxx.50.0.2 xxx.50.0.5 - JSESSIONID=D77772267D276FCEC06BF665CA6E2803 

Workaround

Workaround 1) 

In the Calendar subscription url, add os_authType=none parameter. Hence, if your Calendar URL is: 

/rest/calendar-services/1.0/calendar/export/subcalendar/private/8ce6244a879edf1f5be6aa2e654978d833083020.ics 

, it should look like this:

/rest/calendar-services/1.0/calendar/export/subcalendar/private/8ce6244a879edf1f5be6aa2e654978d833083020.ics?os_authType=none 

(Only for MS Outlook) Workaround 2) 

As an alternative, you could subscribe to your Calendar URL using Outlook Web App (OWA), as described in the Microsoft KB article You can't add an Internet calendar in Outlook 2019, Outlook 2016, and Outlook for Microsoft 365