- Plesk for Linux
- Plesk for Windows
Unable to send an email with the following message:
CONFIG_TEXT: 554-example.com (hostname) ESMTP Service not available
554-No SMTP service
554 invalid DNS PTR resource record, IP=203.0.113.2
CONFIG_TEXT: 21 Temporarily rejected. Reverse DNS for this IP failed. IB108 The IP address attempting to send mail does not have reverse DNS setup, or the DNS lookup failed. Verify the sending IP address has reverse DNS setup before resending the email.
On Linux servers, the following error appears in the
CONFIG_TEXT: postfix/smtp: ... ESMTP Service not available 554-No SMTP service 554 invalid DNS PTR resource record, IP=203.0.113.2
CONFIG_TEXT: Jun 5 08:16:57 hostname postfix/smtp: 52D2D44039: to=<email@example.com>, relay=recipient.com[203.0.113.111]:25, delay=323220, delays=323220/0.02/0.02/0, dsn=4.0.0, status=deferred (host recipient.com[203.0.113.111] refused to talk to me: Service not available - no PTR record for 203.0.113.2)
There is no DNS PTR record for the sender's hostname:
# dig example.com A +short
# dig -x 203.0.113.2 +short
PTR (reverse DNS) record is missing for sender's hostname. The mail message is rejected due to security policy on the recipient side.
If Plesk DNS server is used, add PTR record for the domain using KB article: How to add a DNS record for a domain in Plesk.
In case an external DNS server is used, it is required to contact Internet Service Provider (ISP) in order to add appropriate PTR records.
Note: DNS propagation usually takes 24-48 hours.
To view the hostname the of mail server (if Postfix is used) do the following:
1. Connect to the server via SSH;
2. Run the following command:
# grep myhostname /etc/postfix/main.cf | grep -v "^#"
myhostname = example.com