Using an allowed user list with VSFTPD

A cursory glance doesn't show anything wrong with your config file... the problem may lie elsewhere.

You've probably already tried this but it might be worth checking the following:

• Make sure that that whatever user vsftpd is running as has the appropriate privileges on /etc/vsftp.user_list. You don't have your own non-privileged user configured with the nopriv_user directive, but the default is nobody.
• Try commenting out the chroot_local_users directive to see if there is an issue with chroot-ing.
• Have you restarted the vsftpd process after making changes? A common Doh! sysadmin moment for me is I make the config changes but forget to HUP to the process... (embarrassing, yes I know).
• Try running vsftpd directly from the command line so any errors go to STDERR.
• Have you configured your user streams to have /bin/false as a login shell? Try using /bin/nologin instead. /bin/false will prevent that user from logging in at all.
• As a last resort consider using PAM and virtual users.