==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release):      1.6.8
- Deployed with iRedMail Easy or the downloadable installer? installer
- Linux/BSD distribution name and version:  Debian 12
- Store mail accounts in which backend (LDAP/MySQL/PGSQL): Mysql
- Web server (Apache or Nginx): Nginx
- Manage mail accounts with iRedAdmin-Pro? yes
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.
====

I want to add an existing domain to my iredmail Server.
I wanted to do this via:
How to Host Multiple Mail Domains in iRedMail with Nginx

I Have already changed the Zone File and

>host mail.new-server.de shows the right ip-address.

now I tried to follow the steps in the above Howto and added the lines in the /etc/amavis/config.d/50-user file, but when I try to restart the amavisd daemon (with amvis restart), I get:

Error in config file "/etc/amavis/conf.d/50-user": Can't locate object method "DKIM" via package "0" (perhaps you forgot to load "0"?) at /etc/amavis/conf.d/50-user line 495.

line 495 is read:
DKIM

Does anybody know what's wrong?