I'm not so sure. I send 1 million+ emails a month from my server, and have had no issues at all in terms of being on blacklists. Deliverability has been compara

I'm not so sure. I send 1 million+ emails a month from my server, and have had no issues at all in terms of being on blacklists. Deliverability has been comparable or better than 3rd party providers. I don't spam, and I don't have very many people sending email from the IP address. Maybe that helps.