adding box in ADS momentum

[sm_ali_sadreghaeni]

hi all
i want to add box to my layout
But momentum shows this message:
ERROR :
Illegal overlap between wall and geometry.
Please change the layout.
Possible cause :
One or more vias touch the box or waveguide
------------------------------------------------
my substrate is
/////GND/////
free space
alumina
////GND////
any one can help me?????

 

[kspalla]

Box and layout could be crossing.
Check each edge and corner of the layout and ensure that layout is with in the box.