A seat is not a bed.

Which train are you trying to book? Origin, destination, date, departure time.

Utrecht centraal (Netherlands) to Regensburg Hbf (Germany) this month

Bestway via oebb.at select for each traveler discount Interrail/Eurail and then the Single/Daytickets option and not the seat only option.
 

Hi, why would I get a day ticket rather than just a reservation? Thanks

You finally get just a reservation the company just made a strange way to get that. For Nighttrains & Trains in Italy.

Thanks - I’ve just done this and it works but only lets me book a seat reservation. How do I book a bed instead of this?

which date exactly? it can happen that the Sleepers and Couchette are arealdy solt out :/

22nd June

THis train is quite populair for -well indeed-what surprise-mostly its beds and -yes indeed- on many dates all beds (/en/ is imprecise: it has both sleeper=bed and couchette=lie down basic bunk, read seat61.com if you dont know all this and see pix) are already taken. Not so much by the Dutch-but by travel eager Germans boarding at the many stops in the Kohlerevier.

IF youre only satisfied with a bed, change dates.

On 22 June, only seats are left.