LES NITA giving divergence problems
 

I am running a LES simulation. After initializing the flow using k-e model, I superimposed the turbulence fluctuations using the /solve/initialize/init-instantaneous-vel command. When I start LES (NITA, BCD, FSM) I get the error divergence in AMG Solver immediatley after 2-3 iterations. Could someone let me know what the problem might be?

Thanks for your help. Anindya