Thanks for the hint.
My cron jobs look like
This has the username field, as used by /etc/crontab.
# /etc/crontab: system-wide crontab
# Unlike any other crontab you don't have to run the `crontab'
# command to install the new version when you edit this file.
# This file also has a username field, that none of the other crontabs do.
SHELL=/bin/sh
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root
1 6 * * * /root/makepwd.sh
# reboot router every day at 05:30
#30 5 * * * sleep 70 && touch /etc/banner && /sbin/reboot
There is only a script called which changes the password for the guest WIFI every day (experimental).
The jobs for rebooting the system are commented out
I cannot find an error here.
Regards Ralf