Eventhough the original question is solved, just a few words about Microsoft:
Microsoft will block your server sooner or later because someone else in the same /24 subnet may have a problem with spam and Microsoft will the block the whole subnet and not just the single IP address of the server.
When you sign up to the JMRP (Junk Mail Reporting Partner Program) and SNDS (Smart Network Data Services) this will not help you either - you will then just be notified when your server get's blacklisted. But getting the server out of the blacklist again will always take a couple of days or even weeks and usually this will only last for a couple of weeks or months before blacklisting starts again.
Therefore you should not run your own mailserver to send e-mail to Microsoft domains at all (hotmail.com, hotmail.co, hotmail.co.uk, hotmail.net, hotmail.dk, hotmail.se, hotmail.fr, hotmail.it, hotmail.de, hotmail.org, outlook.com, outlook.org, outlook.co, outlook.de, outlook.eu, live.com, live.co.uk, live.org, live.de). If you want to run an online shop etc. and need to send e-mails to your customers then get an account at Mailjet, Sendgrid, Postmark etc. and use their services to send mail for you. These services also offer integrations to Postfix, so you can still have your own mailserver to receive mail but use the SMTP provider for you transactional mails to customers.