Email that stopped going to spam

This is the work nobody sees and that costs a company the most. An invoice goes out, the customer never receives it, and a week later a salesperson is asking why nobody replied.

The cause is usually the same: a DNS zone that gained records with every new tool over the years and never lost any. Records were left behind by services the company no longer used, some of them contradicted each other, and there were too many to take in at a glance.

Mail servers have no way to guess which record still applies. When they cannot decide, they file the message as spam — and tell nobody.

So this was not "setting up DNS" but clearing out: removing everything that no longer belonged, and leaving one unambiguous answer to the question of who is allowed to send mail on the company's behalf.