The following steps will assist you in checking your outgoing mail settings in Outlook 2016:
1. Open Outlook 2016.
2. From the menu, click on Tools, followed by Accounts.
3. Select the e-mail account that you wish to check from the column on the left-hand side of the Accounts window.
4. Locate the Outgoing server and ensure that this is set to mail.yourdomain (e.g.: mail.example.com).
5. Place a tick in the Override default port box and change port number (located to the right-hand side of the Outgoing server) to 587.
6. Ensure that the Use SSL to connect box is unticked.
7. Click on the More Options button.
8. In the window which opens, ensure that the following settings are used:
- Authentication: select User Name and Password from the drop-down field.
- User name: this must be your full e-mail address (e.g.: firstname.lastname@example.org).
- Password. This is the same password that you use for your incoming mail.
- Unqualified domain: This field must remain empty.
9. Close the Accounts window.