Why does my site IP address get Blocked?
An important first step to make sure email sent from your IP isn’t blocked is to review its status on known ‘blacklists’.
Review instructions, in our article: Determining if a server is blacklisted: https://kb.iweb.com/hc/en-us/articles/230267148-Determining-if-a-server-is-blacklisted.
You should also verify your server’s mail queue content or outbox (current size and outbound email traffic statistics) to identify unusual activity levels.
Follow these instructions to unblock your IP from Hotmail / Outlook:
1. Ensure Compliance: https://mail.live.com/mail/policies.aspx
2. Follow best practices and FAQs: http://postmaster.live.com/Troubleshooting.aspx
3. Configure your reverse DNS on your IP addresses: https://kb.iweb.com/hc/en-us/articles/230242968-Configuring-Reverse-DNS-Control-Center-or-Customer-Hub-
This issue might be happening because the Microsoft system is not recognizing the IP or your domain and is treating it as spam.
This feature prevents unwanted spam from reaching customer’s mailbox.
To request for white listing from Microsoft please use this link https://sender.office.com/Delist/