Hello, I have more than 18 years of experience in System Administration, Network Administration, DevOps, Cyber Security, and many other IT fields. I worked many years as a sysadmin and DevOps for a web hosting company. Depending on the problem it may need that you change some configurations before starting the Delisting process else it may worst than before. Sometimes the problem may caused by behavior of your mail traffic which causes false positive.
Regards,