Question What "admin@localhost.localdomain"?

[Zoo3]

What "admin@localhost.localdomain"?

Subject: Undelivered Mail Returned to Sender
...
The mail system
<admin@localhost.localdomain>: unknown user: "admin"

I receive the above email irregularly to my registered email address. I can't find any entries registered as admin@localhost.localdomain when I log in with Admin and look at the profile and check the full hostname. hostname -f command is also fine. I'm the only user (administrator) of my Plesk.

Where is admin@localhost.localdomain set up?

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Plesk 18.0.42

 

[IgorG]

Have you modified line

mydestination = localhost.$mydomain, localhost, localhost.localdomain

in /etc/postfix/main.cf? What is the output of command:

# hostname -f

 

[Zoo3]

I don't use email on Plesk, so I haven't set anything up at all.
The relevant section of main.cf is described as follows

mydestination = localhost.$mydomain, localhost, localhost.localdomain
#mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain
#mydestination = $myhostname, localhost.$mydomain, localhost, $mydomain,
#       mail.$mydomain, www.$mydomain, ftp.$mydomain

hostname -f

My domain will be displayed.

 

[IgorG]

Try temporarily change line

mydestination = localhost.$mydomain, localhost, localhost.localdomain

to

mydestination = localhost.$mydomain, localhost

and check if it helps.

 

[Zoo3]

Thank you. I changed it that way. However, I am not sure when I will receive that email, so I am going to wait for a while for it to arrive.