Send Mail Task fails in SSIS package

I got the following error when start debugging my SSIS package when setting the "Microsoft Exchange" as SMTP Server in the SMTP Connection Manager.

Error: 0xC002F304 at Send Mail Task, Send Mail Task: An error occurred with the following error message: "Failure sending mail. System.Net.WebException: The remote name could not be resolved: 'Microsoft Exchange'"

If I use the SMTP Server name from the Ping SMTP.mysite.com, I got the following error.

Error: 0xC002F304 at Send Mail Task, Send Mail Task: An error occurred with the following error message: "Mailbox unavailable. The server response was: smtpout03.dca.untd.com Authentication required".

Please help me if you see my error.

Thanks!