I have two CalDAV calendars - one for tasks and one for a regular calendar. The task calendar is assigend to no email address and the regular calendar is assigned to the email address, where I'm receiving calendar invites (I did that in calendar settings). The issue is, that I'm getting error 80004005 when I try to accept or decline a calendar invitation. When I look at details in the error window, it seems that for some reason Thunderbird tries to accept the invite with my task calendar, which is not possible (the server refuses that). This is happening despite the fact the task calendar is not assigned to be used with my email. Based on my calendar settings, Thunderbird should be accepting the invite with the regular calendar. I tried removing all calendars and then adding them in various orders, but always with the same result. I tried this on two devices with the same result. After deleting the task calendar, invite accepting works fine again (but I don't find that to be a solution). I'm running version 78.10.0 Thanks for any help!