Cannot resolve name of the outbound SMTP server - Event 6856 (SharePoint 2010 Products)


Applies to: SharePoint Server 2010, SharePoint Foundation 2010

Alert Name:   Cannot resolve name of the outbound SMTP server

Event ID:   6856

Summary:   Microsoft SharePoint Foundation 2010 sends alerts and other administration messages by using an SMTP mail server. You can specify which SMTP server to use, and you can set the e-mail address to use for sending alerts and receiving replies for all sites, by using the Outgoing E-Mail Settings page of the SharePoint Central Administration Web site.

Symptoms:   The following symptoms might appear:

  • Cannot send e-mail by using SPUtility.SendEmail

  • Cannot send e-mail messages, including alert e-mail, confirmation e-mail, invitation e-mail, and e-mail about exceeding quota 

  • This event appears in the event log: Event ID: 6856 Description: Cannot resolve name of SMTP host <host id>.

Cause:   One or more of the following might be the cause:

  • Microsoft SharePoint Foundation cannot connect to the SMTP host.

  • SharePoint Foundation 2010 cannot resolve the name of the outbound SMTP server.

To resolve this issue, use the resolution that corresponds to the cause that you identify. After performing the resolution, see the “Verify that an e-mail message is sent” section at the end of this article to confirm that the feature is operating properly.


You must be a member of the Farm Administrators SharePoint group to perform the following actions.

Resolution:   Start and configure the SMTP service

  1. Start the Internet Information Services Manager 6.0 Manager and in the tree view expand the name of the server.

  2. Right-click the SMTP virtual server that is used by SharePoint Foundation (for example, Default SMTP Virtual Server), and then click Start.

  3. To configure the virtual server, right-click the virtual server and click Properties.

  4. On the Delivery tab, click Outbound Security.

  5. In the Outbound Security dialog box, either the Anonymous access or Integrated Windows Authentication option is selected. If Integrated Windows authentication is selected, make sure that the SharePoint Foundation Central Administration application pool account has access to the SMTP service. Select the Account and Password check boxes, and type the Windows account name and password that grants you access to the computer to which you connect.

Resolution:   Configure outgoing e-mail settings in Central Administration

  1. On the Central Administration page, click System Settings and in the E-Mail section click Configure Outgoing E-Mail Settings.

  2. On the Outgoing E-Mail Settings page, in the Mail Settings section, type the correct SMTP server in the Outbound SMTP server text box.

Verify that an e-mail alert is sent

  1. Navigate to a SharePoint Foundation Web site that has a list of any type.

  2. Click an item in the list.

  3. Click an item in the list and on the ribbon, click Share & Track.

  4. Click Alert Me and from the menu select For this item.

  5. In the New Alert dialog box, in the Send Alerts To section, type the account name in the Users text box.

  6. After verifying other settings, click OK.

    An e-mail message is sent to the e-mail Inbox informing you that you have created a new alert.