Well wat i did is the following. Because i run docker/mailcow inside a lxd container/vm nefilter is not working. I make a cronjob that will retrieve the blocked ip adresses every minute and write them to a textfile. This textfile will be store on my internal webserver.
because of this i created my own ip banlist. I use opnsense as my firewall. My firewall will read the file and refresh the file every 2 minutes and will then block the ip adresses that are in the file.
So this way i created a workaround for my issue that netfilter is not working on my system.(only blocking meganism)