Why can't I place a bed in minecraft?

So I just built a house in minecraft and I can't place a bed on the second floor, but I can place it on the first floor. The first and second floor are the EXACT same size, so I know it's not a matter of size. Help anyone?

Added (1). The material I'm using to place it on are wood platforms

Cap n

It depends on what material you are attempting to place it on

simple

What material are you trying to place your bed on? Are you trying to place it on two spaces, while standing on a third space?

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