HFSS IE Simulation Problem

HI,

I use HFSS 2015 version for simulation of ant+radome using HFSS IE.
I use datalink simulation, so i simulate antenna only with FEM method and simulate radome with IE datalink.
But, the simulation stop at pre conditioner lu factorization step always.
I really don't know the reason.

my simulation condition is below.

1. frequency : 77GHz
2. Ant type : 7elements series array antenna
3. radome size : 70mm x 60mm x 2mm(W x L x H)
4. Simulation method : FEM method(Antenna Only) + IE using datalink(Near Field Source condition)

Please.