CC can't see local books

Hi,

I use CC without problem on my Kindle fire. But now I loaded it on an no-name android tablet which claims to be running Android 5.12 (which I'm not sure is a real release).

I have gone into settings to select my default drive, and in settings, I can see the books I loaded by USB.

But when I go back to the library view or the grouping drawer, it says my library is empty.

Any idea why I can't see my side loaded books?

I also tried sending to device from Calibre, and save to disk from calibre, and I can't see those either (but I can on my fire)

Liz