Proftp 服务器在登录时给出“没有这样的文件或目录”，即使目录存在

我在https://www.howtoforge.com/tutorial/proftpd-installation-on-debian-and-ubuntu/之后在新的和更新的 Debian Jessie 8.7 上设置了一个新的 proftp 实例，但新用户再次断开连接（任何用户 -甚至 root e=when allowed) 成功登录后：

03:20:55 ~$ ftp otrupload@ftpserver:21
Connected to ftpserver.
220 ProFTPD 1.3.5 Server (Debian) [192.168.1.101]
331 Password required for otrupload
Password:
230 User otrupload logged in
Remote system type is UNIX.
Using binary mode to transfer files.
200 Type set to I
local: 21 remote: 21
229 Entering Extended Passive Mode (|||49865|)
550 21: No such file or directory
221 Goodbye.
03:22:14 ~$

我的配置如下所示（我将其修剪以查看发生了什么）：

# Set off to disable IPv6 support which is annoying on IPv4 only boxes.
UseIPv6                         off
# If set on you can experience a longer connection delay in many cases.
IdentLookups                    off

ServerName                      "Debian"
ServerType                      standalone
DeferWelcome                    off

MultilineRFC2228                on
DefaultServer                   on
ShowSymlinks                    on

TimeoutNoTransfer               600
TimeoutStalled                  600
TimeoutIdle                     1200

DisplayLogin                    welcome.msg
DisplayChdir                    .message true
ListOptions                     "-l"

DenyFilter                      \*.*/

# Port 21 is the standard FTP port.
Port                            21

MaxInstances                    30

# Set the user and group that the server normally runs at.
User                            proftpd
Group                           nogroup

# Umask 022 is a good standard umask to prevent new files and dirs
# (second parm) from being group and world writable.
Umask                           022  022
# Normally, we want files to be overwriteable.
AllowOverwrite                  on


TransferLog /var/log/proftpd/xferlog
SystemLog   /var/log/proftpd/proftpd.log



<Global>
    RootLogin   off
    RequireValidShell off
</Global>

DefaultRoot  /ftpshare/

<Limit LOGIN>
    DenyGroup !ftpgroup
</Limit>

的主目录otrupload是\ftpshare

# echo ~otrupload
/ftpshare

它具有以下权限：

drwxrwxrwt  2 otrupload otrupload      4096 Jan 30 06:04 ftpshare

有什么建议吗？它在我上次安装时工作，我遵循完全相同的方向？