Dekstop client "operation Canceled"

Hi all, I’m experiencing problems with desktop client version 3.1.3 Windows 10.

The exe was installed successfully, but when the sync begin after some files it stop with message “could not be synced due to an error”.

The first problem is that i cant find the log file, or better i see one in the nextcloud folder but is always empty, the second… is there only me or any one else is having this issue ?

My server is a local one, in my LAN, installed on an Ubuntu 18.04

The client is installed on an other PC inside LAN, the android client is working fine.

Thanks in advance.