This appears to be have been broken in the last update to the Android Aura app.
I did report this so far no fix.
You can view recordings using the Windows version of VLC.
Try installing bubble upnp and VLC to your tablet. Bubble upnp can login to the Aura 4K media server and VLC can be set to display full screen 16:9 assuming your tablet is 16:9. You can watch Live TV and recordings. I think you will have to buy a bubble upnp licence. Bubble upnp requires a external media player and VC works real well.
I have my Aura set wake at 06:30 every morning so I can watch Breakfast TV on BBC 1 which has the local news.