No height map data was available. That's a bummer.
If you're way at the poles, that's probably why. Orbital measurements only go
so far away from the equator.
If this area is filled with water, try a box that has less water. That's
probably a good idea for gameplay reasons anyway.
Otherwise, this could be a problem with terrain.party. Retrying the link above
at a later time might help, or try posting it in the Discuss link for help.
At any rate: there's no height maps here. Sorry!