Please follow the below steps to configure the Parent Paths for your domain(s) in HELM control panel :
1. Login to HELM control panel.
2. Click on "Domains". You will see your domain listed on the page. Click on it.
3. You will see all the menu options listed and one of them is "Advance Domain Options". Click on the "Advance Domain Options" icon.
4. Click on the "Parent Paths" icon.
5. Make sure the "Parent Paths" is set to "Enabled" from the drop down list on top of the page. This is the configuration for your main domain -- yourdomain.com to have "Parent Paths" support.
6. You may further enable or disable the parent path support for your subdomain(s) by setting the status to enable or disable which available at the bottom of the page.
7. Click Save once you have the changes made.
Note: Due to some version different between HELM Control Panel, you may enable Parent Path with step as below.
Follow Step 2 as above, select on Web Site Settings, checked the Parent Path checkbox.