How to fix Outlook / Hotmail email deliverability issue?

We don't guarantee email deliverability since there are some email service providers that block some Mail servers / hosting based on some reasons and outlook/Hotmail are one of them., However, we are not blocked by major email providers like i.e Gmail, etc. So unfortunately since we have no control over their own white-listing policy we won't be able to do anything from our end.

Also, you can get in touch with the Outlook support team and they will explain and you provide any additional details if you want.