I split you off into your own thread. It seems unlikely that you’re having the same issue as that other user, since their issue was deck/note/note type-specific.
But if you were – then you would need to start by trying everything suggested for them.
- Blank screen when trying to study cards - #2 by Danika_Dakika [although you can skip that if this is only happening on your AnkiMobile install, and not on desktop Anki]
- Blank screen when trying to study cards - #3 by Anon_0000
- Blank screen when trying to study cards - #5 by Danika_Dakika