Permission denied for shared calendar in Thunderbird

[A Former User]

Hello,

we are trying to access a shared calendar through caldav using thunderbird.
I have set access permissions for my calendar to be accessed by another user. With kopano WebFrontend I can access the calendar from the user I shared the calendar with.

If I try to access this calendar from within Thunderbird I get the error that the credentials where not accepted.
Message in ical.log:

Tue Jul  5 10:45:52 2022: [error  ] Unable to open IPM_SUBTREE object: no access (80070005)
Tue Jul  5 10:45:52 2022: [error  ] Error opening IPM SUBTREE using user "XXXXXX": no access (80070005)

Used CalDAV link: https://server.xxxxx.yy:8443/caldav/USERNAME/Calendar

If I add the user to the Administrator group, I can access the calendar from Thunderbird.

What could I do, to access a shared calendar from a user without Administrator privileges?

kopano version 8.7.19.0

Regards
Ulrich

[A Former User]

Hi,

case closed.
Deleting all permissions for shared calendar and also deleting permission “folder visible” for the mailbox folder.
Restart of complete kopano server and create the appropriate permissions it works.

Ulrich