sshd does not start after installation anymore

After installation with "--ssh-permit-root --ssh-password-authentication" the following file was created:

/etc/ssh/sshd_config.d/custom.conf

containing:

Created by the ISPConfig autoinstaller on 2022-12-29

PermitRootLogin 1

PasswordAuthentication 1

openssh-server 1:8.9p1-3 does not like this syntax and refuses to start.

I was using ssh for the installation itself, since it took place in an KVM guest.

After commenting the two lines out everything works normal so far.