You may need to call Xerox, I've had the same thing with FileZilla and had to switch to IIS, I'm not sure they ever made a workaround or fix.
Check that there are no lock files in the root
Verify the FTP account has delete permissions
Verify if the MFP is using Passive/Active and try the other
Post the logs from FileZilla for the Xerox failure, maybe somebody will see the issue:
Here is two logs I dealt with between a Xerox and a Konica, It ended up being switched to IIS and it worked for both machines
KONICA SUCCESS:
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> 230 Logged on
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> CWD /
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> 250 CWD successful. "/" is current directory.
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> TYPE I
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> 200 Type set to I
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> PORT 192,168,0,69,180,169
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> 200 Port command successful
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> STOR SKMBT_C454e17031615460.pdf
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> 150 Opening data channel for file upload to
server of "/SKMBT_C454e17031615460.pdf"
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> 226 Successfully transferred
"/SKMBT_C454e17031615460.pdf"
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> QUIT
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> 221 Goodbye
(000016) 3/16/2017 16:47:02 PM - scansfz (192.168.0.69)> disconnected.
Then we have Xerox, not short, not sweet, just a lot of apparent garbage
(000017) 3/16/2017 16:52:59 PM - (not logged in) (192.168.0.31)> Connected on port 54256, sending
welcome message...
(000017) 3/16/2017 16:52:59 PM - (not logged in) (192.168.0.31)> 220-FileZilla Server 0.9.60 beta
(000017) 3/16/2017 16:52:59 PM - (not logged in) (192.168.0.31)> 220 Welcome to ABS FTP
(000017) 3/16/2017 16:53:00 PM - (not logged in) (192.168.0.31)> USER scansfz
(000017) 3/16/2017 16:53:00 PM - (not logged in) (192.168.0.31)> 331 Password required for scansfz
(000017) 3/16/2017 16:53:00 PM - (not logged in) (192.168.0.31)> PASS ********
(000017) 3/16/2017 16:53:00 PM - scansfz (192.168.0.31)> 230 Logged on
(000017) 3/16/2017 16:53:00 PM - scansfz (192.168.0.31)> SYST
(000017) 3/16/2017 16:53:00 PM - scansfz (192.168.0.31)> 215 UNIX emulated by FileZilla
(000017) 3/16/2017 16:53:00 PM - scansfz (192.168.0.31)> PASV
(000017) 3/16/2017 16:53:00 PM - scansfz (192.168.0.31)> 227 Entering Passive Mode
(192,168,0,120,202,196)
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> OPTS UTF8 ON
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> 202 UTF8 mode is always enabled. No need to
send this command.
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> CWD /
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> 250 CWD successful. "/" is current directory.
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> MKD
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> 501 Syntax error
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> OPTS UTF8 ON
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> 202 UTF8 mode is always enabled. No need to
send this command.
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> CWD
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> 250 Broken client detected, missing argument
to CWD. "/" is current directory.
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> PASV
(000017) 3/16/2017 16:53:21 PM - scansfz (192.168.0.31)> 227 Entering Passive Mode
(192,168,0,120,234,34)
(000017) 3/16/2017 16:53:42 PM - scansfz (192.168.0.31)> QUIT
(000017) 3/16/2017 16:53:42 PM - scansfz (192.168.0.31)> 221 Goodbye
(000017) 3/16/2017 16:53:42 PM - scansfz (192.168.0.31)> disconnected.