i used now this command which worked:
certbot certonly --webroot-path /home/website/public/ -w /home/website/public/ -d trustserv.de -d www.trustserv.de -d postfixadmin.trustserv.de -d roundcube.trustserv.de -d mta-sts.trustserv.de -d matrix.trustserv.de -d matreg.trustserv.de
i could modify the certbot.service file but would really like to just issue a: certbot renew