Shell CAD.obj does not support testing for inside
 

Help needed please: I tried running snappyHexMesh after running blockMesh but I came up with the error below:

--> FOAM FATAL ERROR:
Shell CAD.obj does not support testing for inside
Probably it is not closed.

From function shellSurfaces::shellSurfaces(const searchableSurfaces&, const PtrList<dictionary>&)
in file autoHexMesh/shellSurfaces/shellSurfaces.C at line 134.

FOAM exiting