Not all files backed up

I’ve just purchased a My Cloud EX2 Ultra with 4GB storage in RAID1 config. I’m using WD SmartWare to do continuous file backup of photos from my Win10 PC to the device. I’ve successfully backed up over 60k photos so far but there are 254 that just sit there pending backup. I just cannot get them to backup. I’ve tried all the suggestions i#ve read about other software holding them etc but to no avail. Anything else I can try?

You could refer to the following link: https://support-en.wd.com/app/answers/detail/a_id/17455