Confluence Team Calendar - Outlook iCal sync problem - sign in popup

[Niklas]

Hello everyone,

since we updated your Confluence (Data Center) to the lts version 9.2.0 we have problems with the iCal sync between Confluence and Outlook 2016/Outlook 2024. The Problem still appears with Confluence 9.2.1 (LTS).
If you subscribe an Confluence team calendar with iCal and put the ics file url into Outlook the first sync is working fine. But at different times an windows security popup appears and ask for credentials. Nothing is working here so you can only cancel and the calendar sync can't process. (result: no updated calendar)

In Confluence we have private team calendar url activated so you should not need credentials. Also the first calendar sync after an Outlook restart always works fine.

With Confluence 8.x.x. we had no problems with it.

I hope someone can help.

[Torsten Müller]

Unfortunately, the above link does not solve the problem for us. With Confluence data center 9.2.3, this problem still exists.

I took a deep dive into this, and found out that the problem is related to the session cookie being sent back with the API response. Using the Postman Http tool, I observed the following behavior:

1. send the request to the team calendar rest API. 

2. The host will return the vcal data AND a session cookie

3. On the next request, this session cookie is being sent back to the confluence host. NOW confluence insists on authorization data, which leaves two options:

4a: send the response adding an authorization header with an API token. This will generate a successful response.
4b: alternatively: delete the cookie from my jar. Requesting the calendar ressource without the cookie will then also generate a successful response.

One thing that needs clarification: in step 3, the server will not _Always_ demand authorization on the second connection attempt. It may be the 3rd, the 100th, and sometimes it will even work for hours before starting to demand authorization. Unfortunately, I have not been able to find any trigger that will reliably cause the confluence host to demand authorization for the call.

We have users that have very actively used the ical feature from Team calendars in the past. Ever since updating to 9.2.x, this feature does no longer work as advertised. 

[Torsten Müller]

Folks, basically at the time of my posting, this issue has been added, which also provides at least a temporary solution by adding ?os_authType=none to the ical url. 

See: https://jira.atlassian.com/browse/CONFSERVER-100059  

[Srinatha Tondihal]

Below thread seems to have solution for your issue. 

https://community.atlassian.com/forums/Jira-questions/Reason-for-the-popup-from-Outlook-asking-sign-in-to-https-api/qaq-p/2413474