9F services 9114, 9112, 9126, and 9150 are travelling to Amsterdam via Brussels. While the Amsterdam destination is opened for sale for the entirety of the booking horizon, the Brussels stop is only opened from 5 weeks before departure.
We are aware that there is an availability discrepancy which displays a full availability of all booking classes to Brussels on these trains, which may not in fact reflect the situation in real life. When a user attempts to sell a class that is not available (although displayed) an error message is presented and the sell therefore has failed.
The sell failure occurs due to the mapping of booking classes between our rail system and the GDS, for Brussels only, and we are working to remedy the issue.
In the meantime, please check Eurostar.com for the actual price availability.