https://www.geogebra.org/m/dv86k7uy
The graph shows error when you visit the above site. But if you click the "undefined" text twice and click somewhere else, the graph gets plotted. Question is: why the graph has no '$z$' points plotted?
Explanation of the question: The graph $1=xyz$ should have $z$ that looks like this: https://www.geogebra.org/3d/n5m2jjx7 (example $xz = 1$) but in the graph $1 = xyz$ the $'z'$ points are not considered?
Implicit 3D plot are not yet implemented in GeoGebra.
You must enter $z=\frac{1}{xy}$.