CentOS / RHEL 9 64 bits

Installation instructions

Logs Download 
sudo wget -O /etc/yum.repos.d/zammad.repo \
  https://dl.packager.io/srv/zammad/zammad/stable-backport-issue-5859/installer/el/9.repo
sudo yum install zammad

More details can be found at https://docs.zammad.org .