I am planning to book a ticket from Zurich HB to Paris Gare de Lyon on 6th July. When searching, I see a direct train option at 15.34, duration 4 hr 4 mins. But when I select that option to book tickets, it always shows a popup that “Unfortunately, there are no longer any tickets available for the connection you have selected”. I tried to book the same train for a later date as well, but the same popup appears.
Not sure what the issue is. Are the bookings for that train not open yet? Is it due to the scheduled maintenance on that route?