using /spawnpoint with commandblocks sends you to the void in superflat

I made 3 maps with /spawnpoint in it and it kept doing that, What I did was i put a pressure plate on Y 201 a block at Y 200 and the command block at Y 199 with the command "/spawnpoint @p" doing that would originally put you on the block above, and now it sends you to the void, so yeah