mail user manage (qmail + vpopmail)

Virtualmin 1.556
installed from interface address is private, and NAT env.

disable postfix and dovecot, and setup qmail + vpopmail from src.

virtualmin setting: qmail + vpopmail

it works qmail + vpopmail cli and virtualmin,
“create virtual server”, “add a user to this server (create mailbox)”.

but do not manage user from “Edit Mail and FTP Users”,
and do not create ftp user.

how can i manage email user and create ftp user ?