Chess960 did not allow castling for black - why? Bug?

I just played my first game of Chess960 on lichess.

My opponent castled earlier in the game.

When I tried to castle, as black, it could not be done. Why?

I was trying to castle on my move; instead I timed out. My king was not in check nor was there a check to any intervening squares. Neither my king nor my rook had moved!

Here is the game:

How did you try? Did you try to move your king on your rook? Because this is the way to castle in chess960.

Thank you. Is there somewhere I should have learned this arcane spell? Or does every new 360 player have to write a forum topic to find out?

There is a settings for this in your config:
https://lichess.org/account/preferences/game-behavior#castleByMovingTheKingTwoSquaresOrOntoTheRook

I think I've seen somewhere a note that only the "king on rook" is an option in Chess960 but apparently it's not on the config page and I don't remember where did I see it.

@palom said in #3:

Is there somewhere I should have learned this arcane spell?
Sorry, I can't remember how I learned this.

It's probably because some Chess960 castlings cannot be performed the standard way at all - like if your king started on f1 and the rook is on h1, moving your king to g1 just moves your king to g1 so if you want to castle, you have to do it by Kxh1.

And the king can also be already on g1 in the starting position.

@mkubecek said in #4:

There is a settings for this in your config:
lichess.org/account/preferences/game-behavior#castleByMovingTheKingTwoSquaresOrOntoTheRook

I think I've seen somewhere a note that only the "king on rook" is an option in Chess960 but apparently it's not on the config page and I don't remember where did I see it.

You probably saw it at https://lichess.org/variant/chess960

I thibk there is a place in Lichess where you see the rules of every variant.