Hi, Exchange 2007 installed on the user site, Outlook works fine with the setup of server type "microsoft exchange". When I chose the server type with POP3, the account test is successful. But in this way, could not send the email to externals. Send/receive email from internal is fine. could also receive email from external,but not send If log into webmail by IE, everything is fine send/receive emails from externals. It all works fine before, but recently problem mentioned above happened. I did not change any setting in the server side. Could anyone please help on this? Thanks a lot. Regards, Lily

Please help here. Thanks!

What error you get when you try to send external mails while you have POP3 configured outlook? Do you get any NDR? Also post the output of Get-ReceiveConnector *\Client* | FL here...Amit Tank | MVP Exchange Server | MCITP: EMA | MCSA: M | http://ExchangeShare.WordPress.com

it is fine now, the point is the setup in outlook at user site. There is option "SMTP authentication" needs to be checked. Thank you. Regards, Lily