How to Reject email if email address (recipient )doesn't exist?

Hey Nethserverians!

Could anyone guide me on how to reject emails if the email doesn’t exist?

for example:
the email address doesn’t exist but if someone send an email to that address still I receive those emails on I want to implement a mechanism where when someone sends an email to an email address that doesn’t exist on my domain then the mail server should reject email immediately. So, the sender will receive a rejection email.

Thanks a lot!

NethServer Version: NethServer 7.7.1908
Module: Email

hum check the domain settings inside the email application, I guess that you have enabled the Accept unknown recipients to root.

Normally it is the default behaviour to reject unknown email address

Mar 9 12:32:03 prometheus postfix/lmtp[20269]: 3993218D27B8A: to=<>,[/var/run/dovecot/lmtp], delay=0.51, delays=0.49/0/0.01/0.02, dsn=5.1.1, status=undeliverable (host[/var/run/dovecot/lmtp] said: 550 5.1.1 <> User doesn't exist: reply to RCPT TO command))