Exchange 2000 uses smtp authentication for sending mail. You need to have them modify their 'account' properties on outlook express to include their username and password for smtp. They might only have it for pop3. It may not fix your problem, but it's a good place to look. -----Original Message----- From: Christian Kurmann [mailto:ckurmann@xxxxxxxx] Sent: Friday, February 01, 2002 7:25 AM To: [ExchangeList] Subject: [exchangelist] Relay problem http://www.MSExchange.org/ Hi everyone. I have a problem with some Internet freemail accounts. I have an exchange2000 sp2 setup. Some of our workers complain that they can't reply to emails that are sent to their exchange Mailbox. This problem only occurs when the people use Internet Email, and send the reply or mail from there. If they use the OWA or the normal MS exhange Server Email, there is no problem. It also only happens with some adresses not with all. I haven't knowingly blocked any Email adresses or providers. The Error message is (translated from Germann) "the message could not be sent because the recipient was refused by the server. Server answer: "550 5.7.1 unable to relay for reby_g@xxxxxxxxxxx", (account: "domainname", SMTP-Server: "exchange.domainname.ch", error number 0x800ccc79). Can Anyone help me out on this? Thanks alot ------------------------------------------------------ You are currently subscribed to this MSExchange.org Discussion List as: jrobill@xxxxxxxxxxxxx To unsubscribe send a blank email to $subst('Email.Unsub')