Trying to get the RTRR/FTP Backup station function working

[wilcal]

The following are notes taken during my testing

Remote Source IP: 192.168.0.55 ( Port 21 )
Local qnap NAS target: DataVol1/Public/ftp_test ( Read/Write/Execute to everyone )
Remote source: /home/wilcal/ftp_to_nas
Plenty of drive space everywhere

For some reason I don't understand how this works. I have a remote ftp server at 192.168.0.55
It's an RPM Linux box and the test source directory is /home/wilcal/ftp_to_nas
It has a normal simple USER_ID & Password. Using FileZilla I can get to this user and directory
from any number of workstations on the LAN and download and upload files. The FTP port is 21.

Using:

Backup Station -> RTRR (Real-time Two -way Folder Sync) it seems to set up all correctly
and using the test function in the setup I get the following response:

Test success at 116.548 MB/s

The setting up sees both the local ( target ) and the remote ( source ) directories.
There are just a handful of 7 files to synchronize with. All seems to go well but ends
in an error. The Logs indicate the following:

Job encountered a remote I/O error or no space left on the destination device! Begin 1st retry.

Bad port number or the service is not available! Begin first retry.

Backup Station -> RTRR (Real-time Two -way Folder Sync)
Create a Replication Job
Synchronize/Remote folder to local folder
Configure Remote Host Settings 192.168.0.55; FTP Server, Port 21, Passive mode, PASV or EPSV
Enable maximum transfer rate disabled
Test success at 116.548 MB/s

This looks to be the same problem opened on 18 Mar 2019
viewtopic.php?f=15&t=147521&hilit=RTRR+ftp

Please share some hints to Try
Thanks

[dsnider]

I just want into this problem today, so it definitely has not been properly resolved.
What is funny, is that it has no problem deleting files from the server, but has problems PUTing files to the server.
It's clear that the problem is that it is trying to upload the files with the full path specified, without the leading slash.

To fix it, I had to temporarily create directories in the root file system.

It's also ludicrously slow, and it replaced files that already existed -- huge files, I don't know why!