Sogo send email to a different domains with same user name fails

NethServer Version: 7.6.1810 (final)
Module: SOGo Groupware

I have exchange server and sogo with different domain names.
The sogo mail server is sending and receiving emails from gmail, and others.

I tried to send email from sogo - admin account to user in the old server, I have a similar user in sogo server

after writing the email and pressing send it shows this message

Cannot send message: all recipients are invalid

Please have a look at:


and post the section at the time, where you have tried to send the mail.

Maillog could be useful too

i think you must set under
domain (change)
and set relay to another server

Thanks everyone for your reply, I Solved the issue. It was my mistake joining the domains.