Is it a bug?

Blacks to move and I can't castle (O-O), is it a bug in analysis

Click the king, then the destination square, or drag the king to the destination square.

To Martin : it doesn't work, that's the problem!

I'm not seeing any issues.

This is the second time in 2 days that someone reports this bug. So it probably is a bug. They should report it.

I only report bugs that I can recreate.

However, based on the screenshot the rook was the last piece selected so it's trying to move the rook. I know there is a change in castling where clicking the King and then the Rook it does not castle, but selects the rook. The exception I think is in 960 Hanes where that still works.

I'm not 100% sure that's fully released but if that is what is being tried, that explains why it isn't working.

Has the Black king or the Black rook moved prior to the castling attempt?

I'm trying to move the black king two squares to the right to castling as the rules say, but the black rook doesn't move..

As Martin said, the rook was the last selected piece as your screenshot showed. Which means when you click on a square, the rook will move to that square. To castle, you need to select the king. Just like the OTB touch-move rule regarding castling.