From normal mode to nightmare mode

I’ve cleared from 1-1 to 10-10 in normal mode with 3 stars, but I can’t get into nightmare mode.

What should I do?

Is there anyone else who can’t change from normal mode to nightmare mode?

My ID is 9kk76q
My Server is Mirror Lake

@dentalfloss Thank you for reaching out. Please give us some time to investigate your issue. While we are doing this, can you please manually save your game data by clicking settings->save game so we can grab your latest data? Thank you for your patience!

Hi @dentalfloss,

You can switch the difficulty by clicking the difficulty icon on the bottom-left: