iCloud for Windows not uploading all photos from Upload folder

iCloud for Windows on Win10, iCloud software is up to date, Windows updates up to date.

Problem is that iCloud software is not synchronizing all photos from Upload folder. It synchronized 193 out of 219 and will not progress beyond that.

Restarted Windows and iCloud app numerous times. No change.

Is there any log file to at least check what is happening inside?