You will likely need to provide more information if you want to receive some actual help. At least screenshots of the GUI from both sides, and possibly logfiles will be needed to be able to see what is actually going on.
OK, it looks like the problem was a disconnect between the sync engine and the UI. I rebooted the target device and the job suddenly showed significant progress. Apparently files were being transferred that weren’t being reported to the UI.
However, the service doesn’t detect the mounted drive immediately after a reboot. Usually it picks it up after a while, but not this time. I had to click ‘Rescan’ in order to kick it into gear.
Once the current scan is done I expect to be able to see download traffic and to provide a report.