When adding the Admin Center to a WAS ND Profile you get the error CWWKF1203E: Unable to obtain the following features: [adminCenter-1.0], this is because the version of Liberty Profile for WAS is < than 8.5.5.4
Install a newer fixpack ie use Google to search for WAS Liberty 8.5.5.4 fixpack and follow the links to download and install using IM (IBM Installation Manager). If you have not installed WAS Liberty with IM, then you will have to install a new extracted version of WAS Liberty 8.5.5.4 and migrate the appropriate folders from the existing instance into the new instance.