注释掉 /etc/pam.d/vsftpd 文件的 auth 两行即可

#%PAM-1.0
session    optional     pam_keyinit.so    force revoke
#auth       required    pam_listfile.so item=user sense=deny file=/etc/vsftpd/ftpusers onerr=succeed
#auth       required    pam_shells.so
auth       include  password-auth
account    include  password-auth
session    required     pam_loginuid.so
session    include  password-auth

若解决不了可参考另外三种解决方案