No valid reverse DNS entry

[segundo95]

Hello Goodnight; Can you help me solve this problem blocking some domains.
The message that shows is the following:

ECDHE-RSA-AES256-GCM-SHA384: 256 CV = no: SMTP error from remote mail server after RCPT TO: <[email protected]>: 550 5.7.0 Your server IP address [17x16x-1x1-12x] does not have a valid reverse DNS entry [17x16x-1x1-12x.static.example.org]. See http://spamauditor.org/best-practices/check_dynamic_reverse_dns for more information. Protection provided by MagicSpam 2.0.18-1 http://www.magicspam.com

 

[keat63]

Is this a new server ?
If so then you will need to ask your service provider or data centre to configure RDNS at thier end.
This isn't something that can be done at your end as far as I'm aware.

 

[nixuser]

Please contact your hosting provider to set rdns for your server IP address.

 

[cPanelLauren]

In some cases, providers do delegate access to add a PTR record though this is not the standard. You might check with them if they do allow you to add this the instructions here should be useful: How to Configure Reverse DNS for BIND in WHM - cPanel Knowledge Base - cPanel Documentation

Otherwise, you'll need to have your provider add a valid PTR record as suggested by @keat63 and @nixuser