Question message could not be delivered

[gherardos]

Hi,
I have a Linux server on ionos.it
I have configured the domain to receive emails on plesk.
from plesk the email leaves and reaches the recipient.
if the recipient replies, his email comes back with the following message:

This is the mail system at host example.com:
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<john@example.com:>: unknown user: "john"

Do you have any suggestions?
Thanks
Gherardo

 

[gherardos]

segue:
Reporting-MTA: dns; example.com
X-Postfix-Queue-ID: 4F2F2460D0
X-Postfix-Sender: rfc822; prova@prova.prova
Data di arrivo: Tue, 1 Dec 2020 13:58:21 +0000 (UTC)

Destinatario finale: rfc822; john@example.com
Destinatario originale: rfc822; john@example.com
Azione: fallita
Stato: 5.1.1
Codice diagnostico: X-Postfix; utente sconosciuto: "john"

 

[rahulkshinde]

Hello,

What are the MX records for your domain? is it pointing correctly.

 

[gherardos]

Yes, it pointing correctly.