I see that train is an OBB Nightjet, so you definitely need a reservation.  

What is your travel date?

@Marcus King  @Kwankwan 

As the Nightjet Amsterdam - Zürich runs as a Joint Venture of German Rail ans Nightjet you can use this Nightjet (like the Nightjet Berlin/Hamburg - Zürich) in seating carriages without any reservation. (Still highly recommened especially for Berlin or amsterdam to Zürich ) 

Seats reservation can be done for 4€ via bahn.de or for 3€ via oebb.at by using the seat only options. 

For couchette and sleepers you need ofcourse reservations these can be bought via oebb.at by following the manual in "How to get reservations".

It may also depend on the date-there is the odd week or so when apparently this train does NOT enter the NL. And somehow I get the impression that OeBB also has a kind of quota for passholders-on a recent samesame Question I tried out and it would show very expensive seats but NO passholders supplmy for them, using the other method.

BTW; your profile says you are in NL- but dutch people cannot use EU-rail-it has to be INterRail.

I recently booked the 3 last couchettes on the 25 May Amsterdam - Innsbruck service. There was also still one sleeper bed available. All for the pass fare, so no trace of any quota.

So please provide a specific example (origin, destination, date, departure time) where you saw this.

Hi

I have the same problem, trying to book on Saturday 4th June, but it says “reservation not possible”. I’ve tried dates around and it’s the same every day…

Did you find a solution on your side? I can’t see anything on OEBB website that indicates works. 

I was able to reserve a seat in the DB Navigator app.
You can enter the same train times. Instead of selecting the Nightjet, select IC 60403.
Then go to offer selection, enter your age, and click on “Reservation only”.

I see available couchettes and sleepers on 4 June from Amsterdam to Zurich:

Is this the relation you'd like to book? I suspect you chose "Seat only” but for night trains it work differently. Please follow these steps.

Thanks for this. I did try that as a fallback option, but when I came to paying, the website said that leg could not be booked...

I see available couchettes and sleepers on 4 June from Amsterdam to Zurich:

Is this the relation you'd like to book? I suspect you chose "Seat only” but for night trains it work differently. Please follow these steps.

Thanks for this, I’m looking for Zurich - Amsterdam, not Amsterdam - Zurich.

I have booked other Nightjets which were fine (Brussels-Vienna and Vienna-Rome) but I’m stumbling on this one.

Then it's fully booked. That's Whitsun weekend so maybe that's why. You can still book with departure on 3 or 6 June but not in between. Or there might be engineering works and the trains haven't been released for booking yet, although that would already be a bit short-term and therefore unlikely. But you could ask SBB or DB just to be sure.

Thank you...will have to revisit the itinerary then !

@bibousig maybe this is an alternative for you? You could try to see if there’s place on this other night train.

Zurich 1959 - Hannover 0601 (NJ 40470 / IC 60400)

Hannover 0641 - Frankfurt 0900

Frankfurt 0926 - Amsterdam 1329

Or you can travel with normal trains to a station somewhere in between, find a good hostel, and do the rest in the morning.

ÖBB would have said on twitter that these dates still haven't been released for booking.

Please note, that the carriages with the seat cars run as Intercity, this means reservations are optional. You get them with the seat only option via DB or ÖBB. Maybe due to the ongoing planning about the works, could be not possible yet to reserve like on the carriages of this train that run as Nightjet with couchette and sleeper cars. 

If you only need a seat I would wait will the release of the timetable, if you want a couchette or sleeper maybe think about traveling with the Nightjet to Hamburg and change in Hannover on the IC to Amsterdam

When these dates will finally be released, there will still be couchettes and sleepers available, since nobody can book right now.

Thank you everyone for all the feedback, it seems the reservations have become available now! Yaay :)

As we have two young kids with us, couchettes are preferred for us !

Thanks again