WebDAV + rclone fails with 401 Unauthorized when using 2FA (app password)

I’m trying to set up synchronization between Mailbox.org Drive and a local directory using rclone on Linux.

After enabling 2FA on my Mailbox.org account, I created a separate app password specifically for rclone, but I’m unable to authenticate via WebDAV.

Setup:

* OS: Debian 12

* rclone version: 1.70.3

rclone config:

* Storage type: webdav

* WebDAV vendor: other

* URL: https://dav.mailbox.org/servlet/webdav.infostore/Userstore

* User: name@custom-domain.dk

* Password: app password (format: xxxx-xxxx-xxxx-xxxx)

Test command:

rclone ls mailbox:

Result:

ERROR : error listing: couldn't list files: 401 Unauthorized

NOTICE: Failed to ls with 2 errors: last error was: couldn't list files: 401 Unauthorized

Notes:

* The app password was created after enabling 2FA

* Login via web interface works as expected

* This setup worked previously before enabling 2FA (using normal password)

* No special headers or advanced config used in rclone

Questions:

1. Does Mailbox.org WebDAV support app passwords when 2FA is enabled?

2. Is the WebDAV endpoint (`/servlet/webdav.infostore/Userstore`) still correct for this use case?

3. Are there any known limitations or additional requirements when using WebDAV with 2FA-enabled accounts?

4. Has anyone successfully used rclone with Mailbox.org Drive and 2FA enabled?

Any guidance or working configuration examples would be appreciated.

Thanks in advance.