rdiff-backup keeps crashing when trying to save files on nextcloud server via webdav

Hello!

I just signed up to the forum and trying to find my way around. I 
apologize in advance for any duplication in case my question has been 
raised and solved before, I certainly don't want to steal anybody's 
time. However, in this case I would still appreciate any help to find 
the solution. On my own I was not successful yet ...

I am currently trying to backup my files to a cloud storage space, which 
is on a managed nextcloud server. The provider does not offer any 
ssh-connection, instead I have to use the webdav protocol. Now I have 
big problems, because the backup keeps crashing. The process quits with 
a whole bunch of confusing error messages, like "[Errno 2] No such file 
or directory: '/var/crash/_usr_bin_rdiff-backup.1000.crash'" or 
"OSError: [Errno 5] Input/output error."

Here is the command that I used to start the backup:

    rdiff-backup -v9 --exclude  ~/Dokumente/2019 --exclude
    ~/Dokumente/2020 --exclude  ~/Dokumente/2021 --exclude
    ~/Dokumente/2022 --exclude  ~/Dokumente/Archiv_2007-2018 --exclude 
    ~/Dokumente/nextcloud_Helds --exclude ~/Dokumente/nextcloud_HH
    ~/Dokumente ~/mnt_nextcloud_veitsbackups/VeitsBackups/Dokumente >
    protocol_14.9.2023.txt

The attached file shows both the output to the terminal (rows 1-102) and 
the content of the logfile which I produced by adding the "> 
protocol_14.9.2023.txt" suffix to the linux command line.

Is there any known reason why I cannot push my files to the server? I am 
running on version 2.0.5 as this is the version that Linux Mint has in 
the repository. My system is

     Kernel: 5.15.0-83-generic x86_64 bits: 64 compiler: gcc v: 11.4.0 
Desktop: Cinnamon 5.6.8
     tk: GTK 3.24.33 wm: muffin dm: LightDM Distro: Linux Mint 21.1 Vera 
base: Ubuntu 22.04 jammy

Veit