I use postfix, dovecot and roundcube on my Ubuntu 16.04.
When create new user (unix) then login to roundcube, when I send emails the receiver will get mail from user@localhost instead of user@mysomain.com
If I use sendmail -t from command prompt, emails are delivered with correct
user@mydomain.com
Asking because I recently succeed to broke my postfix and now I am terrified to touch any file :)) So this is a roundcube, dovecot or postfix issue and from where I can correct it.
Thank you in advance,