@skylar @douse_niggers_in_gasoline_and_light_them_up @SunMcNukes @Zerglingman @lonelyowl @burner both outlook and gmail require you to create a postmaster account in their system. DNSSEC can improve scores too if your TLD supports it. Some, like t-online.de would simply refuse mails from small MTAs with no recourse, for them you might need to setup a transport via relay. Sendgrid for example has free plan for small (up to 100 a day) volumes.