X is based on the geometry. So if you have cells in your domain that have a negative X, then you will have problems. Basically in DesignModeler or SpaceClaim you created the domain with negative values of X. Without going back into these programs and having to remesh, the simple solution would be to scale it by adding whatever the min(X) to your X.

Example, if you have a domain that has X values that go to -5 [ m ], change the X to ( X + 5 [m] ).