Hi All,
I have set up an SMTP server.
My site is connected by Cloudflare service with a Plesk control panel.
These marks are all shown in green.
SPF,DKIM,DMARC,MX,DNSBL
Whereas, RDNS is shown in red.
You have changed the SMTP server to a subdomain
mail.mydomain.com
Mail is working normally.
But...