Outlook for Mac Addin is clearing cookies every time task pane is opened

Question

Problem: Every time the user opens the task pane, its asking for login. This is happening only for Outlook for Mac users with latest Sierra version(10.13.3) and Outlook version(16.9). Users with same outlook version and the sierra version(10.12.6) are not seeing this issue.

As the user opens the task pane and enter the credentials, we hit the server and once authenticated, this will send a response headers with Set-Cookie for user_credentials and _app_session. So every time we make a request, we use these cookies to authenticate user. Now when the user closes the task pane and reopens, it’s not sending these cookies as part of the request and we are not able to authenticate the user.

Can anyone please assist me on this?

Answer 1

Issue is with not passing expires value for Set-Cookie. Once we made a change to pass expires value in response headers for Set-Cookie, the issue is resolved.