rDNS/PTR = FAILED, check with your hosting provider! FAILED

Hello,

got this today

rDNS/PTR = FAILED, check with your hosting provider! FAILED

after 2018-12-12 01:42:59 Warning: CSF/LFD Firewall - SECURITY ISSUE
CSF/LFD Firewall contact email for alerts is NOT set on your server, click here to check it.

So added email CSF/LFD Alerts: and the mails are not sending.
Noticed that subdomain was without v=DKIM1 and v=spf1 - added, rebuild mail server - did not help

rDNS/PTR = FAILED, check with your hosting provider! FAILED

here too

Ask your hosting provider to change the hostname of your server (ex: srv.domain.com)

If you using DigitalOcean, you can change the droplet name to (ex: srv.domain.com)

Login CWP.admin :
- Server Setting => Change Hostname (ex: srv.domain.com)
- Email => MailServer Manager = Rebuild Mail Server with the hostname
- Email => rDNS Checker = Check below line :

Another check srv.domain.com resolves to:
srv.domain.com has address 123.456.000 (ur IP address)

Solved - you need to disable DNS only, without the proxy

https://imgur.com/a/OGxLg7M

then you will get
https://imgur.com/a/89bGQpi