carlopmart wrote:
Ralph Angenendt wrote:
Looks like the client wants to have a delivery notfication and postfix answers it. This seems to be a client configuration "problem" if it only happens with one client.
No, this problems occurs on several clients ... And not all are windows clients: my clients are linux, windows and mac.
This happens when the clients want a "delivery report" - please see the mail client configuration.
Ralph