Akonadi / KMail broken imap resource

[Bennett Piater]

Hi,
My IMAP resources broke in Kontact/KMail two weeks ago, and any new instances 
are also broken.
I am completely lost.

My first idea was to try akonadictl restart, followed by fsck and vacuum.
The restart triggered a mariadb migration, which was successful (shouldn't 
that have happened automatically before...?).
However, it didn't change much.

The logs were full of errors like these - the imap resource crashes, with no 
clear cause:

org.kde.pim.akonadicontrol: ProcessControl: Application "/usr/bin/
akonadi_imap_resource" stopped unexpectedly ( "Process crashed" )
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_imap_resource' 
crashed! 0 restarts left.
org.kde.pim.akonadiserver: New notification connection (registered as 
Akonadi::Server::NotificationSubscriber(0x7fe4b02b4f00) )
org.kde.pim.akonadiserver: Subscriber 
Akonadi::Server::NotificationSubscriber(0x7fe4b02b4f00) identified as 
"AgentBaseChangeRecorder - 93936498547840"
org.kde.pim.akonadiserver: Subscriber "AgentBaseChangeRecorder - 
93936498547840" disconnected
org.kde.pim.akonadicontrol: ProcessControl: Application "/usr/bin/
akonadi_imap_resource" stopped unexpectedly ( "Process crashed" )
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_imap_resource' 
crashed too often. Giving up!

There are no further logs that I could find. akonadiconsole doesn't even get 
logs for the imap resource. If I try debugging it, I only see "Error: Not 
really an IMAP resource".

I then tried deleting the mariadb and having akonadi re-create it, which 
helped me once in the past (should be fine since it's only an indexed cache).
Finally, I tried deleting and re-adding the account in kontact.
I also deleted the corresponding files in .local/share/akonadi* and .config/
akonadi*.

None of the above worked. Any ideas how to proceed?
Is there more that I could try to reset? Are there more detailed logs 
somewhere?

This is on arch linux, so I'm running very up to date versions of everything.
My work laptop, also on arch, did not encounter this issue.

Thanks for the great software in any case, I feel naked without it! :D

Note: Please CC me in replies as I am not subscribed to this list.

Cheers,
Bennett