After updating the PTR record for the server's hostname, Email Deliverability is still showing the old PTR record. The interface also indicates the record doesn't match.
The system uses an alternate HELO of “oldPTR.hostname.com”
when sending mail from the “server.hostname.com” domain.
- oldPTR.hostname.com represents the previous PTR record, which was defined.
- server.hostname.com represents the current hostname defined on the server.
cPanel will automatically define the Mail HELO to match the PTR record for the server's outbound SMTP IP addresses. When the PTR record changes, rebuilding the cache would ensure the updated record appears in the Email Deliverability interface.
Rebuild the Reverse DNS Cache via WHM's Exim Configuration Manager. Details on rebuilding the cache can be found in the below documentation URL.
Exim Configuration Manager - Basic Editor - Domains and IPs
Rebuild Reverse DNS Cache and Update Mail HELO
This setting updates the reverse DNS cache and user
domains for mail HELO. This setting only appears when you
enable the Use the reverse DNS entry for the mail HELO/EHLO if available
After rebuilding the cache, check the Email Deliverability interface once more to determine if the issue has been resolved.