Wd Sync cannot synchronize will try later

I can synchronize from my iphone, I can see all the files from my laptop, and make backups, but when I try to sync from the laptop,I get a notice stating that the file cannot be sync and that it wil try later.

Windows 10
My Cloud 3TB

Try to remove the device from WD Sync, then restart your computer. Once restarted, open WD Sync and add the My Cloud again.
Pause and resume the syncing using the icon on the tray.

I’ve tried your suggestion but didn’t work. In some cases, with certain subdirectories, the sync begins ok, but after a few files are procesed, the program hangs!