Unable to login with AD account

Hi all, I have a Big IP LTM and so far our AD user account is working and able to login. We do create one service account for Tripwire but this account can't seem to authenticate or login. It's inside the same AD group which have Admin rights to the F5.

I'm trying to check on the "Secure Password Enforcement list" below but can't find it on our F5 LTM version 12.0.0. Where have this configuration move to ?

Configuring a password policy for administrative users

Use this procedure to require BIG-IP® system users to create strong passwords and to specify the maximum number of BIG-IP login failures that the system allows before the user is denied access.

Important: You must have the user role of Administrator assigned to your account to configure this feature.
On the Main tab, click System > Users .
On the menu bar, click Authentication.
From the Secure Password Enforcement list, select Enabled.
Additional settings appear on the screen.