Cannot book a converation

I had a conversation today and I would like to book a new one in a week. I have enough points, I can see the time available. But the system tells the time I choose is not available.
Could you look what happens? Thank you.

@Ress - Sorry for this inconvenience. It seems to be an issue with Russian interface language. Our development team is already looking into it. Hopefully, it will be fixed soon.

@Galina, you are right. I tried to book again with Russian interface and it did not work. But it is fine with English interface. Thank you.