Hi Tobias,
Did you follow these steps to get the IP address removed from the blacklist? https://technet.microsoft.com/library/mt661881(v=exchg.150).aspx
Levente
On Thu, 21 Jun 2018, Tobias Pape wrote:
Hey,
just a notice that I saw like 5..8 bounces for vm-dev posts because Microsoft (office.com/live.com/outlook.com etc) decides our mailer is spam-banned. I try to clear that up but nothing promised ¯_(ツ)_/¯
-t