They have single-handedly made google look good.

Microsoft in their infinite of wisdom use an IP Reputation system with their free email services; that is, if you have never sent any spam to their clients though have a valid PTR record, SPF, DKIM, DMARC they will silently drop incoming emails to their clients based on their IP Reputation system?

To delve into this further, in the past they have blanket blocked national ISP static IP business subnets, wholesale hosting suppliers, etc.

What this means is that if you run your own server too bad microsoft isnt going to play nice with you even if your static IP has never been blacklisted.

They ban you by default, not based on any valid and logical reasons - do a dig you will find many posts regarding this bullshit approach.

I have lost clients in the past due to them -- i am a small scale supplier so losing even one client due to this is tragic for me --  and i swear micrsoft are the worst people to deal with; that is, i spent 9 months last year dealing with them, only to be placed back on the list for no valid reason again this year. The gist of it is if you are a small player, and not much mail flows between you and them, they dont wanna know you at all and hence why they block you. Pure evil stance from a corporate bully.

They do not own the internet, so sod them. The more people that are aware of their tactics the better, and dont use them unless youre only planning on getting mail from the established boys, that is gmail, apple mail etc and microsoft dont wanna know you.