FreeFileSync Forum

Not sure what I can do to solve this.
It is related to the number of parallel file operations; when I decrease that number, the problem becomes less frequent, only when I set it to 1 no problem anymore.

FFS SYnchronization Settings.jpg

On the server side, settings are as follows, I assumed this ...

I am using FFS (donation edition) to synchronize a number of folders on my desktop PC and laptop (Windows 10) with my Asustor NAS, using FTP. I configured the sync to use parallel file operations.

All the time I am getting error messages, see example screenshot in attachment,
"Cannot read ...