I wanted to book sleepers on the Nightjet from Amsterdam to Vienna (and back) in October '23 and thought I was late booking in June, but the booking site states that tickets are not available.

I called ÖBB and the attendant told me that the connections were not ‘freigegeben’ (open) and told me to try again in July. Does anyone know why that would be, normally you are supposed to be able to book the Nightjet up to 180 days in advance…

I now look each day whether the booking is open, but knowing the reason for it not being open I may know what I am waiting for and when to try to book.

Thanks!