Magnetophoresis simulation. "Evaluation of particle tracing data failed"

Hello all,

I'm currently doing a multiphysics simulation using Comsol 3.5.

I used a Magnetostatics (qa) model where I designed a permanent magnet of 12 by 12 mm with a applied field of 500mT at a distance of 2mm from the surface. At this distance and using a different model of Incompressible Navier-Stokes (ns), I designed a channel of 2mm height and 24mm wide and simulate the fluid flow throughout the channel.

What I'm trying to do is to simulate the trajectory of magnetic particles starting at the inlet of the channel and see how they are influenced by the presence of the permanent magnet.

I already managed to simulate the applied magnetic field and the fluid flow, but once I get to the particle tracing plot I get this message error:

"Error: 8030
Particle Tracing plot failed.
Evaluation of particle tracing data failed"

I already triple check the equations, the boundry settings and subdomain settings. And still I can't see the lines of the particles trajectories...

Has anyone done something like that? Or can anyone give some advice and help?

Thanks in anticipation