Issue Forward-confirmed reverse DNS failed tnmpmscs

[Mark R]

Hi, Can anybody help please

Email rejection error message 'Forward-confirmed reverse DNS failed tnmpmscs'

Plesk is installed on an Ionos VPS
Cloudflare is hosting DNS

Plesk Full Hostname is server.myplesk.com
Ionos Reverse DNS is server.myplesk.com

I have two websites running on Plesk both of which have emails rejected with error 'Forward-confirmed reverse DNS failed tnmpmscs'

Mail-tester.com results.
1) -1.274 RDS_NONE, Delivered to internal network by a host with no rDNS
2) Your server *.*.*.196 ( Plesk IP address) is successfully associated with server.myplesk.com, This may indicate you do not have a rDNS configured for your hostname or the rDNS does not match your sending IP

PTR has been set to the main Plesk IP address of the server, is this correct?
Is this a PTR issue?

Any help would be appreciated

 

[Kaspar]

Your issue seems to match the case described in: https://support.plesk.com/hc/en-us/...dress-to-which-the-chosen-hostname-resolves-2

Do you have Cloudflare poxy enabled for server.myplesk.com? Or are there any other DNS records (either for IPv4 or IPv6) that point to different IP addresses?

 

[Mark R]

Hi,
Typo should read

1) -1.274 RDS_NONE, Delivered to internal network by a host with no rDNS. This may indicate you do not have a rDNS configured for your hostname or the rDNS does not match your sending IP

2) Your server *.*.*.196 ( Plesk IP address) is successfully associated with server.myplesk.com

 

[Mark R]

Hi,

server.myplesk.com is not proxied

the entry looks like this
server.myplesk.com.myfirstwebsite.co.uk

All DNS in cloudflare reference my main Plesk IP

 

[Kaspar]

PTR has been set to the main Plesk IP address of the server, is this correct?

No. You don't need an PTR record.

At your IONOS account make sure you've added the hostname of you plesk server (server.myplesk.com) as the Reverse DNS of you Public IP. See: Overview: Public IP (VPS, migrated Cloud Servers, and VPS+) - IONOS Help

 

[Mark R]

Hi,
already done.

Plesk Full Hostname is server.myplesk.com
Ionos Reverse DNS is server.myplesk.com