Yes I have seen it but I thought it was automatically done when I copy paste the command lines, which is not automatic.
My first mistake was “uninstalling” and “installing” lighttpd instead of “reinstalling” lighttpd.
By the way after a few minutes I have had several errors on nextcloud (23.0.4) with cron which had been fixed by (for newbie like me):
. adding apc.enable_cli=1 under extension=apcu.so in the file /etc/php/7.4/mods-available/apcu.ini
. restart the dietpi-services
. and tested it with sudo -u www-data php -f /var/www/nextcloud/cron.php and checked with nextcloud
Thank you anyway.