Army Portals use a certificate to identify itself to its users and to enable secure connections. If you are receiving a warning that this site is un-trusted / insecure, you will need to install the "DoD Certificate."
To download the DoD Certificates,
i. Go to https://eportal.ctnosc.army.mil/ .
ii. Enter your AKO username and password.
iii. Select the link labeled DoD Root Certificate at the top.
iv. Click the link for Install Root V2.18.A and save the file to your desktop.
v. After the file has completely downloaded, go to your desktop and click on the InstallRoot2.18A file then follow the directions.