Simulation keeps reverting PCGLSS0102 Assembled Stiffness Matrix has a negative diagona

EG 2016-02-13

Hello

I have a spring on which I'm trying to run a simulation (attached). Each time it reaches about 2.4%, it reverts back to 0%. It seems to have a hard time "solving contact constraints". I've already spent almost 9hrs and it is still reverting. The warnings I'm getting are:

PCGLSS0102:Assembled Stiffness Matrix has a negative diagona

Does anyone know why this might be the case? I'm running 2016 SP1.

Thanks

Solidworks Simulation