Send Mail to Hotmail I get Mail delivery failed Returned

The problem I am experiencing is that when a mail being send to Hotmail I get "Mail delivery failed". It doesn't matter what Hotmail email address I am sending to, the result remains the same. Sending to Gmail or official e-mail addresses form no issues.

I discovered this problem when my girlfriend received a booking through the contact form. Upon she wanted to reply via "squirrelmail" it failed. I tested this out on my other website hosted on my same VPS server and also there I was able to replicate the same problem.

I checked if my server has been blacklisted, however my server is clean.

Return-Path: <>
Delivered-To: info@*****.com
Received: from vps1.******.com
     by vps1.*****.com (Dovecot) with LMTP id Gj4MCQj8pVdwXgAAO/oQ6Q
     for <info@******.com>; Sat, 06 Aug 2016 17:02:32 +0200
Return-path: <>
Received: from mail by vps1.******.com with local (Exim 4.87)
     id 1bW37Q-0003rq-2y
     for info@******.com; Sat, 06 Aug 2016 17:02:32 +0200
X-Failed-Recipients: ****@hotmail.com
Auto-Submitted: auto-replied
From: Mail Delivery System <Mailer-Daemon@vps1.******.com>
To: info@******.com
Content-Type: multipart/report; report-type=delivery-status; boundary=1470495752-eximdsn-1376884720
MIME-Version: 1.0
Subject: Mail delivery failed: returning message to sender
Message-Id: <E1bW37Q-0003rq-2y@vps1.*****.com>
Date: Sat, 06 Aug 2016 17:02:32 +0200

Code (markup):

I am stuck, I hope someone has the golden solution.

Thanks in advance.

 

Additional information. It's about the error code "550 SC-001"

Based on the code 550 SC-001, its Mail rejected by Outlook.com for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.

But my server is in good standing??

 

Do you have things like SPF and DKIM enabled for your sending domains ?

If your IP has a poor sending reputation Microsoft has a nasty habit of blocking emails from those so you might have to try and improve or look for a 3rd party to send emails from like sendgrid (can be intergrated into most servers with exim)

 

Thank you for the tip. No, they are not enabled.
What do they exactly do?

I will look at it tonight.

 

@nuffsaid This solved the problem, https://help.directadmin.com/item.php?id=569