So you agree is not about the software but you did not implement best practices with Postfix.
Also, whenever you give an address to someone else, family or friend, risk of going to spam increases.
Links or src in emails without https, higher risk,
Does Maudy prevent you from doing that?
And your sales people will call this a misconfiguration serious enough to fire the sysadmin who did this. The problem is that, typically, nobody trains or supervises the filter applied to the outgoing mail, and nobody is warned that it did, in fact, reject an email, and there is no manual override if the filter is, in fact, wrong. And spammers (from the viewpoint of a particular organization) don't exist and can't exist inside the organization, so any rejected outgoing email is, by definition, a false positive.
