My Ex4100 don't fully backup my mobile files

Hi all,
Maybe this is a known issue.
I have problem with my mobile app and auto backup function.

Generally is working fine, but if for some reason it doesn’t complete a file backup, I cannot find the way to ask to retry and this activity remain stuck.
I tried to cancel the stuck activity from the list, but the file won’t never backed up…

Any idea on how to Force to cross check again the folder for any missing file? Non backup?

Thank you

iPhone or Android?

Sorry, i forgot to mention…it is Android Galaxy S9

Can’t help as i have an iphone. Contact WD Support.