Error when adding multiple CalDAV: "Replay action failed"

[peter_b]

[PROBLEM]
Just ran into the following error when I tried to add an additional CalDAV calendar (source OwnCloud), but:

Error: [calCachedCalendar] replay action failed: null, uri=https://www.my-server.example/owncloud/ ... ser/myuser, result=2147500037, op=[xpconnect wrapped calIOperation]
Source: file:///C:/Users/me/AppData/Roaming/Thunderbird/Profiles/xxxxxx.default/extensions/%7Be2fda1a4-762b-4020-b5ad-a41df1933103%7D/calendar-js/calCachedCalendar.js
Line: 322

Adding that calendar as the first (or only) calendar works fine, but not if other CalDAV calendars already exist in Lightning...

[SOLUTION]
The error message is very cryptic, but the issue is actually that Lightning seems to handle credentials per-hostname.
Therefore, a workaround we've currently applied is to use a different hostname (for the same OwnCloud server) for a calendar that requires different credentials.

Not super-beautiful, but for my case it did the trick!
(Thanks Gil for figuring that out)

[peter_b]

You might get this error also if you previously had CalDAV calendars registered in Lightning, and the credentials stored by Thunderbird's password manager.
In that case, do the following:

1) Remove the stored password for the affected CalDAV host.
You might want to follow the instructions shown in this HowTo: "Thunderbird - Changing the Stored Password"

2) Restart Firefox

After restarting firefox, you should now be asked again for the login credentials for the CalDAV host.