I mean on that page, which they refer to. did you enable DKIM in ISPConfig and create the necessary DNS record?
Yes, the DKIM is enabled on my ISPConfig server admin and DKIM information is also update on both the DNS. Internal (ISPconfig DNS) and on my domain provider.
Again, can you share the error info they give you? You don't have to set it in ISPConfig if ISPConfig doesn't function as a NS for that domain. It's best to remove the zone there.
