Proftp server gives “No such file or directory” upon ;login even though directory exists

I setup a new proftp instance on a new and updated Debian Jessie 8.7 following https://www.howtoforge.com/tutorial/proftpd-installation-on-debian-and-ubuntu/ but the new user gets disconnected again (any user – even root e=when allowed) after successfully logging in:

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 ~$

My Config looks as follow (I trimmed it down to see what is going on):

# 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>

The home directory of otrupload is \ftpshare

# echo ~otrupload
/ftpshare

and it has the following permissions:

drwxrwxrwt  2 otrupload otrupload      4096 Jan 30 06:04 ftpshare

Any suggestions what is going on? It was working on my last install and I followed exactly the same directions?