Hi there,
I can help you with postfix and relay DKIM and spam detection. I would like to let you that I am having 8 years of experience in System Administration in which I have expertise with web hosting, server setup, server configuration, optimisation, migration, server management, Amazon AWS services, cloud servers, WHM servers, Magento 1 & 2, WordPress,DNS, Apache, Ubuntu, Centos, MySQL, Mariadb, PHP, Nginx, Debian,Cpanel, Plesk, Postfix, Exim, Mails, Firewall, Google cloud servers, troubleshooting etc.
I can handle this work perfectly and you will get 100% results.
Looking forward to discussing it further via chat.