If you use the Sitecore message transfer agent (MTA) or if you have configured a custom MTA server, you can verify the connection between the MTA and EXM.
To test the connection between EXM and the MTA:
- In the Content Editor, select the Email root item.
- On the Email tab, in the Server group, click Test Connection.
- If the test is not successful, an error message appears with information to help you troubleshoot the problem.