Was a mail admin for quite a number of years, here is some tips. Check that the ip address you are running your own mail server from is not black listed. Nor ca

Was a mail admin for quite a number of years, here is some tips. Check that the ip address you are running your own mail server from is not black listed. Nor can the IP hosting the mail server be in a home ip range. This is because there is spam black lists that explicitly mark home user ip ranges as possibly spammy. Check the repuation in the various anti spam blacklists out there * Check IP in multiple blacklist http://multirbl.valli.org/ http://multirbl.valli.org/ * Check server IP on mxtoolbox http://mxtoolbox.com/whatismyip/ http://mxtoolbox.com/whatismyip/ * If you are using home server IP please consider using a VPS with a good IP reputation. * Consider lookup up ip at Cisco senderbase reputation and check its score, make sure its consider good. https://www.senderbase.org https://www.senderbase.org * Lookup ip in Barracuda repuation http://www.barracudacentral.org/lookups http://www.barracudacentral.org/lookups (Cisco and Barracuda is because these are somewhat common antispam services at edges).