Login to Direct Admin and click on your target domain name.
Click on Domain Setup.
Tick the box next to the domain name you wish to set as the default domain name and click on Set as Default.
You shall see the successful confirmation message as highlighted below:
Click on Domain Setup.
Tick the box next to the domain name you wish to set as the default domain name and click on Set as Default.
You shall see the successful confirmation message as highlighted below:
Updated on: 06 / 03 / 2020