Error when autoresponder has been sent.

Same situation as some time ago:
A user on one of my domains, hosted on my server enables the autoresponder function within http://mydomain.tld:81/mailuser.
The autoresponderfunction itself works as it should as it performs an automatic reply and the user receives the email which has been sent its emailaddress. So, all works great.

However, when an email has been sent from an emailaddress, which is not on my server, the sender of that email receives an error from its ISP, like:

Action: failed
Status: 5.0.0
Domain name required for sender address username
(in reply to MAIL FROM command)

This means that I miss the @domain.tld (the right part within [email protected]) when the automatic reply has been sent.

So I’ve checked the content of the following files:

/etc/hosts
127.0.0.1 localhost.localdomain localhost
123.45.67.89 host.mydomain.tld host

Within my /etc/postfix/main.cf I have the lines:

myhostname = host.domain.tld
mydestination = /etc/postfix/local-host-names
virtual_maps = hash:/etc/postfix/virtusertable
myorigin = /etc/mailname

Within /etc/mailname I have the lines:
host.mydomain.tld

The output of hostname is:

host.mydomain.tld

And the output of hostname –f is:

host.mydomain.tld

I can not find any mistakes within my configuration, can anyone help me to find out, what I miss?

 

In the mean time, i found out that the automatic replied message, has been sent without any errors to Hotmail accounts.

 

Ok, i confess

It was a little bit stupid, but i did not see the mistake:

There was a line like:

append_at_myorigin = no within my /etc/postfix/main.cf

After removing it, everything is funtioning again.

The problem is solved now. I did it