I think I made a mistake and directly got into the mind flayer prison after I talked to Solaufein near the enterance. I had thought that the daughter was held there. And when I cleaned and left the eastern cavern, the time limit had finished. Now Solaufein doesn't speak to me. Is there anything I can do?

Try reloading. That might be the best thing. It's a bit of a bummer, after having cleared the flayer dungeon. BTW you can just reply to your post below, without having to start a whole new one. People might still be replying to the one below.