Interesting db mail issue. If i click send test mail from sql mgmt studio, it works fine, but when i execute a SP to send a mail, it fails. One thing I noticed is that the "LastModified" column in the mail log shows the domain account when a test mail was sent from mgmt studio, but show "sa" when the SP was used to send mail. 

This is from SQL 2012, did not see this in sql 2008, looks like 2008 always used the service account.  any ideas ?

Get this error:

The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 1 (2013-04-30T16:36:52). Exception Message: Cannot send mails to mail server. (Mailbox unavailable. The server response was: 5.7.1 Client does not

Thanks.

That message came from the SMTP server, not DBMail.  This is not a DBMail issue.

The message indicates the recipient email address does not exist.  Check your email address.

• Proposed as answer by Jason A_ Wednesday, May 01, 2013 6:32 PM
• Marked as answer by Elvis LongMicrosoft contingent staff, Moderator Tuesday, May 07, 2013 1:33 AM

Hi Ranga,

I also use SQL Server 2012. I send a test email through SQL Server Management and the last modified By sa.

If you used stored procedure to send a test email. Please use the command below:

EXEC msdb.dbo.sp_send_dbmail
    @profile_name = 'Adventure Works Administrator',
    @recipients = 'danw@Adventure-Works.com',
    @body = 'The stored procedure finished successfully.',
    @subject = 'Automated Success Message' ;

I can both send test email through SQL Server Management Studio and SP. Make sure you have the right profile. Since you could send test mail via SQL Server Management Studio, please try again to send it via SP.

Thanks.

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As Tom mentioned, these are errors from your SMTP server, and you need to talk to your SMTP people about this. For instance, googling for below gave me several hits:

SMTP 5.7.1