One of the reasons for your success is the fact that you've been doing it for 20+ years. Big providers like Gmail, Outlook, etc all have a scoring system for s

One of the reasons for your success is the fact that you've been doing it for 20+ years. Big providers like Gmail, Outlook, etc all have a scoring system for sender IP addresses and hostnames. The longer your IP and hostname behaves properly, the more credit it will get. I imagine starting a new mail server with new ip addresses/hostnames may be more difficult.