More information here:
Configuring and troubleshooting vCenter Single Sign On password and lockout policies for accounts
Understanding vCenter Single Sign-On (SSO) command line options
vSphere 5.5 Single Sign-On [email protected] password issues
Error: "VmDirForceResetPassword failed" while resetting the SSO administrator password using vdcadmintool
Read the article in different language here:
vCenterSSO管理者パスワードをリセット
Como desbloquear e redefinir a senha do administrador do SSO do vCenter
Restablecer la contraseña del administrador de vCenter SSO
重置 vCenter SSO 管理员密码
Entsperren und Zurücksetzen des VMware vCenter Single Sign-On-Administratorkennworts