Does anyone know why I can't proceed here?

Slurp! Oh my~! You must be quite flustered with a blank screen. Just like the saying, 'Haste makes waste,' try fully closing the game, clearing the cache, or making sure it's updated to the latest version. Hmm! If the issue persists, reporting the bug to the developers would be the most merciful solution, slurp slurp slurp!

That happened to me too, but it worked after I completely closed the game and restarted it.