Hello, we got serval messages from our customers. They send us mails from their customers, in their mails we can see following error message: SMTP error from remote mail server after RCPT TO:<mail@address.com>: host XEAMSHOSTNAME [XEAMSIP]: 550 5.1.1 No such user here - code 420. What could that be? The Spamfilter should forward all emailmessages and let the exchange servers behind decide whether there are user or not. How can we configurate that?