Stop sent emails showing "On Behalf Of" in outlook 2016

[Rincewindwiz]

Hi All
I am using MS Office Outlook 2016 with Windows 7
I own the domain mydomain.com
I use a wide vareity of email addresses to send mail all of which end in @mydomain.com
If I send from a different email address than my default email address, outlook shows this as
Sent by default email address on behalf of sent-from email address.
For example:

[FONT=&quot]From: Fred <[email protected]> on behalf of sentfromEmailAddress@mydomain.com[/FONT]


How do I prevent this and have it simply shows as coming from the sent-from email address so simply

From: [FONT=&quot]entfromEmailAddress@mydomain.com
[/FONT]


TFAI