Enable email invitations for CalDAV servers

Hi there,

I use a radicale CalDAV server to synchronize my calendars between my devices, which works fine so far.

But when I add some participants, Thunderbird will not send out any invitations. radicale has no such feature, thus Thunderbird should take care of this. This article at the knowledge base (KB) describes exactly what I want to achieve. However, the Prefer client-side email scheduling option is greyed out (cannot be activated). Sure enough, I have assigned an email account to the calendar.

The KB article states:

This option will be only visible for CalDAV calendars but not for any other type of calendar

Since this is a CalDAV calendar I do not understand, why the option is greyed out. For CalDAV calendars hosted on NextCloud servers, the option can be activated. IMHO this option should be available for all CalDAV calendars, like described at the KB article.

Or am I doing something wrong here?

I don’t think that you do much worng her. This part of TB seems to be not very flexible.
I experience a similar problem. For a CalDav calender hosted on my NAS, email invitations were not sent either. Then I saw the option " `Prefer client-side email scheduling". In my case it was not greyed out and I could use it.
However, instead of using the the email address which was assigned to the calendar, the invitations were sent with the organizer “username@local.host” where I found no place where I could explicitly set the email address of the organizer. Even just deleting the organizer entry in the invitation popup and repacing it with the email address which was used for sending the invitations did not change anything.
On the other hand, when using a O365 account evrything works just as you want to have it. This is sad because main reason for using TB is to avoid using MS stuff.

You might find others discussing this at https://connect.mozilla.org/ or https://support.mozilla.org/