My setup: OS: Debian 11 (bullseye) Thunderbird version: 78.11.0 Install source: Debian repos Summary: I have a self-hosted instance Baikal (a WebDAV server). I have succesfully used two applications other than Thunderbird to sync to this server: vdirsyncer (CLI) and DAVx5 (Android), so I know the server is working. I am having trouble subscribing to a calendar from this server with Thunderbird. The nature of the problem I encounter depends on what I've selected for Baikal's "WebDAV authentication type" config option. When I choose "Digest" or "Apache", the problem is that Thunderbird never prompts me for a password. I can add the calendar and give it a name just fine, but the password prompt is never shown. When I switch to the calendar view, the calendar remains greyed out. When I click "ENABLE", the calendar flashes onto the window momentarily and then reverts to its original state. When I choose "Basic", Thunderbird prompts me for a password, but then the calendar page shows a ⚠️ icon next to the calendar in question, and when I hover over it, the tooltip reads "The calendar Master is momentarily not available" Details: The setup dialog asks for a username and URL. I provide my DAV username; for the URL, I have tried both: * the generic Baikal DAV url (https://my.baikal.domain/dav.php) * the URL suggested in this official Baikal guide (https://my.baikal.domain/calendars/[username]/[calendarname]/) The latter does NOT work to produce a password prompt on "Basic" authentication. After I enter these details, the next dialog window asks me to name the calendar, and asks for an email address to associate with it. I have tried both leaving it blank and selecting the email address associated with my DAV account; the result is the same. In one help thread I found online, someone suggested enabling the `calendar.network.multirealm` option in the config editor; I've tried this to no avail. Thanks in advance for any help.