I can't place the block using /fill command in the flat world

I can't fill the block using /fill command to fill 95 4 -405 187 4 -357 in a flat world,it said that I can't place the block outside the world border,but I try to use /fill to fill 15 3 -238 14 3 -237 in the same flat world and it works,it can works normally.I only can place the block one by one in 95 4 -405 187 4 -357.