New storage Sub-folders

Hi,

I’ve just connected a new WD Element external HD to my GL-AR750S (already have 2 others connected - work fine). I can see it on the Network Storage page (http://192.168.8.1/#/nasview) and on the Gl-inet app. My problem is that the sub-folders under the main folder aren’t visible (ex. element 2\Athletics Videos\sub-folders). Does anyone know how to fix it?

In advance, thank you