From the MDaemon console:

Select Security

Select Security Settings

Expand Sender Authentication

Select SMTP Authentication

Select Authentication Is Always Required when mail is from local accounts

Select Apply

Select OK 

With SMTP Authentication enabled on the server, the local sending clients will need to be configured to send messages using SMTP Authentication. 

For Outlook 2013:

Select File

Select Account Settings

From the drop down, select Account Settings

Select the MDaemon account

Select Change

Select More Settings...

Select the Outgoing Server tab

Select My outgoing server (SMTP) requires authentication

Select the radio button for Use same settings as my incoming mail server

Select OK

For Outlook 2010:

Select File

Select Account Settings

From the drop down, select Account Settings

Select the MDaemon account

Select Change

Select More Settings...

Select the Outgoing Server tab

Select My outgoing server (SMTP) requires authentication

Select the radio button for Use same settings as my incoming mail server

Select OK

For Outlook 2007:

Select Tools

Select Account Settings

Select the MDaemon account

Select Change

Select More Settings...

Select the Outgoing Server tab

Select My outgoing server (SMTP) requires authentication

Select the radio button for Use same settings as my incoming mail server

Select OK

Comments

The incoming and outgoing server can be the same information you use to connect to WorldClient.