They also block people who send very little mail. If you only send one or two per month to their consumer domains you don't build enough 'reputation'. I know f

They also block people who send very little mail. If you only send one or two per month to their consumer domains you don't build enough 'reputation'. I know for a fact my mail server never sent any spam because I logged everything. It was only me using it. But every few months I got banned from sending to live.com. I have one friend there. They didn't mark anything as spam. We just sent personal emails. There's a form where you can unban it but it kept happening. In the end I stopped running my own, it was so much hassle.