Can't castle....can't work out why.

Either there's a rule I don't know or my game has crashed.

Game no. 15889

I'm trying to castle queen side but it won't let me. In anticipation of
possible responses I can safely say....
1) Neither king not rook has moved yet
2) No there are not any pieces between them!!
3) I'm not in check nor would I be moving through check.

Any ideas??????/

Unless you're not doing it the right way ie: moving your king two
squares towards your rook - it's a mystery!

It works now.......hooray!

A temporary glitch I guess...