Microsoft has 2 major anti spam systems which work’s separately
Office 365 – Which include all the 365 systems
Hotmail – Which include the free systems like hotmail.com, live.com, outlook.com etc.
in order to request de-list from black list you first need to make sure your server is clean :
check for RBL listing :
MXtoolbox - https://mxtoolbox.com/blacklists.aspx Hetrix - https://hetrixtools.com/blacklist-check DNSBL - https://www.dnsbl.info/dnsbl-database-check.php
The check for open relay
mxtoolbox - https://mxtoolbox.com/diagnostic.aspx DNSgoodies - http://www.dnsgoodies.com/
After all is well you can ask for de-list :
office 365 - https://sender.office.com/ hotmail - https://support.microsoft.com/en-us/supportrequestform/8ad563e3-288e-2a61-8122-3ba03d6b8d75