For workflow purpose all incoming emails are cc/forwarded to a external vendor email e.g.
Emails to firstname.lastname@example.org is cc'd to email@example.com.
Whenthe vendor tries to reply to the email and cc firstname.lastname@example.org, they get a bounce mail to email@example.com - error message below
"556 Cannot accept message from this email address"
We are using Postfix, the vendor is using Lotus Notes. Anyone has experience this error msg before with lotus notes?