I have found that this error repited constanly every few second in my nextcloudpi
Could you please post output of:
sudo ncp-report
This will help to get more information.
Here it is
Is there a specific reason for using an OS (Debian 10) which is EOL (end of life) and a Nextcloudversion (NC23) which is EOL?
Because I have autoupdate and I thought that it will be update automatically. But I will try to update, when I have time to backup all data