Family Folder not available to users?

Hello all, I hope someone can offer some advice:

I have a My Cloud Home Duo, linked to Virgin Media Superhub 3.0. I have nine users setup to see and use the Family folder. It seems that for the last couple of weeks some people are struggling to see the folder at all - when opening their app they get the message along the lines of “Nothing here yet, click add files”. It seems they are getting to my Home Duo but not seeing any folders/files. Even more curiously, my wife can see everything she should on her Mac, but only her own files on her Android phone and not the Family Folder. I have no idea if these things are linked? It doesn’t seem to make any difference whether we are on the local network or using the internet.

Does anyone have a clue what I should be checking?