Mycloud app does not access device files

My Cloud OS 3 Personal & Network Attached Storage My Cloud EX2
1

In the Mycloud app, I can remotely access files on my ex2 ultra, but in “mobile device”, I can see but not open files. Even selecting a file and choosing “open with” does nothing… no drop down of apps to chose from.

This happens on both my phone (admin) and my partner’s phone on her share.

Any one else have this?
Pete