Spam mail from own mailserver, but there is no outgoing mail in postfix log? [duplicate]

Today I received a phishing mail from my own (valid) sender address (info@example.com).
I checked the e-mail header and see the mail was received by my valid mailserver.
Received: from mail.example.com ([::1]:36128) by domain.1blu.de (kopa… Continue reading Spam mail from own mailserver, but there is no outgoing mail in postfix log? [duplicate]