Fix Hotmail Block on cPanel IP

Emails sent from my cPanel-hosted domain have suddenly stopped landing in Hotmail / Outlook inboxes. There is no listing on public black-hole services and Microsoft support insists the IP is not formally blocked, yet every message to @hotmail, @outlook and @live addresses is silently dropped.

Key context
• The mail is generated by the default cPanel mail service (Exim).
• No recent changes were made to DNS, SPF, DKIM, rDNS or server configuration.
• My only troubleshooting so far has been opening a ticket with Microsoft; the response pointed me to general guidelines without lifting the block.

What I need
– A thorough diagnosis of why Microsoft is filtering or throttling the IP.
– Remediation steps applied (SPF / DKIM / DMARC alignment, rDNS, HELO banner, SNDS/JMRP enrolment, reputation clean-up, etc.) until test messages deliver successfully to a live Hotmail account.
– A short hand-over note outlining the actions taken so I can keep the configuration healthy going forward.

Acceptance criterion
At least three consecutive test emails from the server must reach the inbox (not junk) of a Hotmail/Outlook account and show no policy-related errors in the headers.

Root access to the VPS and full control of DNS are available the moment we start.