@Joulinar:
Thank you, the faulty system time was the cause of the error. apt update now ran without errors. I should have noticed it myself, sorry.
Kind regards and stay healthy!
Edit:
After only a few minutes of operation, the system time is already slowing down again, what can be done?
root@DietPi:~# timedatectl status
Failed to create bus connection: Datei oder Verzeichnis nicht gefunden
root@DietPi:~# sudo nano /etc/systemd/timesyncd.conf
root@DietPi:~# date
Fr 23. Apr 15:39:37 CEST 2021
root@DietPi:~# sudo ntpd -qg
sudo: ntpd: Befehl nicht gefunden
root@DietPi:~# cat /etc/fake-hwclock.data
2021-04-23 13:17:01
root@DietPi:~#
/etc/ntp.conf does not exist.
Now I studied this thread:
https://dietpi.com/forum/t/wrong-time-after-power-off/3181/1
and changed the NTP server from pool.ntp.org to Gateway, the problem isn’t be solved.
root@DietPi:~# date
Fr 23. Apr 16:22:18 CEST 2021
root@DietPi:~# systemctl status fake-hwclock
● fake-hwclock.service - Restore / save the current clock
Loaded: loaded (/lib/systemd/system/fake-hwclock.service; enabled; vendor preset: enabled)
Active: active (exited) since Fri 2021-04-23 15:49:37 CEST; 32min ago
Docs: man:fake-hwclock(8)
Main PID: 113 (code=exited, status=0/SUCCESS)
Tasks: 0 (limit: 4915)
CGroup: /system.slice/fake-hwclock.service
Apr 23 15:49:37 DietPi fake-hwclock[113]: Fri Apr 23 13:49:37 UTC 2021
Warning: Journal has been rotated since unit was started. Log output is incomplete or unavailable.
root@DietPi:~#
Any ideas here? Thank you.