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Issue Undelivered mail - SMTP port 25

andre_c

New Pleskian
Server operating system version
Ubuntu 22.04.2 LTS
Plesk version and microupdate number
18.0.51
Hello,

although smtp port 25 is enabled in the panel, plesk is unable to send emails from the various password reset systems or automated emails with the various cms installed

VPS IONOS Provider
 
Have you checked /var/log/mail for entries associated with mail attempts? Normally you can find hints there why a mail cannot be sent.
 
This can be accessed from either Tools & Settings > Assistance & Troubleshooting > Log Browser or through SSH (Linux console).
 
Ionos is one such provider that has port 25 blocked by default. You need to contact their support to unblock it.
 
This can be accessed from either Tools & Settings > Assistance & Troubleshooting > Log Browser or through SSH (Linux console).


Nemesis ESMTP Service not available 554-No SMTP service 554-Bad DNS PTR resource record. 554 For explanation visit SMTP Error Messages of the IONOS Mail Servers - IONOS Help



554 Bad DNS PTR resource record​

Problem:

Email from your email server has been rejected because the PTR resource record (PTR-RR) of your IP address does not comply with IONOS policy.

Solution:

Switch from a dynamically assigned IP address to a fixed IP address.

Verify that the PTR-RR is the default generic entry of your provider. Assign your email server its own full domain name (FQDN).
 
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