Problem with the SMTP mail

Prejudice, or a problem with the SMTP mail
NethServer server or domain example:
When sending a mail to a person who is not registered on NethServer but uses it externally from the remote server does not NethServer gives me the following error:

(There was an error when sending mail. The mail server responded:
5.1.1 Recipient address rejected: User unknown in virtual mailbox table.
Check the message recipient "" and try again.)

How can I do to solve this problem and send mail to the person who is not connected to the server and connected to the server but NethServer Remote.

Hi Antonio, you need to make custom transport map, search on forum once i have made custom transport maps

HI @k1000,

As we can see domain has one MX domain record.
So maybe you need to specify only relayhost to the

[root@nethserver postfix]# dig MX

;; ANSWER SECTION:               10447   IN      MX      10

[root@nethserver postfix]# dig

;; ANSWER SECTION:          13335   IN      A

I get this off
See the attachment

@k1000 ,
Thanks for clarification.

So now describe the scenario of how mail should pass through those servers.