Due to the security requirements of the AKO/DKO portal DKO users are required to register their CAC to the DKO portal. This is because AKO/DKO is an Army hosted portal and we do not have the access to personnel records outside of the Army with an equivalent ability to verify your identity. Registering your CAC to your account is how AKO/DKO primarily validates the identity of users outside of the Army/Department of the Army.
New DKO accounts require a CAC to be registered. For any other account that is a full DKO account but does not have their CAC registered the user will be forced to register their CAC to their account before being able to do anything else. This is often a result of an already existing account switching to a DKO account type.
After you register your CAC to your account you can elect to access DKO with your username and password.
For more information about registering for DKO please see DKO ACCOUNT REGISTRATION
For more information about registering your CAC to the AKO/DKO portal please see HOW TO REGISTER YOUR CAC TO AKO