Tag Archives: smtp

SMTP Relay email stuck at Queue folder

During my SMTP Relay setup, i noticed the Send email function is called successfully BUT no email is sent to my mailbox.

I check the following directory C:\inetpub\mailroot\Queue and noticed that there are a few EML file stuck in it.

After googling and troubleshooting, the problem is that in the IIS6 > SMTP’s Properties > Outbound Security, the Basic Authentication is specified with an invalid email address and password.

Update them and now my email will be sent out.

#160009: The e-mail address ’emaill address’ is unknown

Bumped into this error when setting Office 365 Relay in my Local SharePoint On-premise server for outgoing email.

I have done the following steps -> http://fmuntean.wordpress.com/2008/10/26/how-to-configure-iis-smtp-server-to-forward-emails-using-a-gmail-account/

Ensure you have done the add SMTP Feature, IIS 6.0 SMTP Virtual Server running.

The below check/config works for me


  1. Go to your IIS 6.0 and right click SMTP Virtual Server properties.
    smtp relay email address unknown error - properties
  2. In the Server properties, go to “Security” tab and ensure the Service Account (or whatsoever account) that needs to do the mail sending, is added into the operators list.
  3. smtp relay email address unknown error
  4. That is it! You can refer to my post Powershell script to test SharePoint Send Mail