NaN or Inf found when solving linear system using SOR in Turbulent (k-e)

Hi,

I am trying to model mixing using k-e turbulent model in a stirred tank. I am using the same geometry and physics set-up as mentioned in the mixer modular tutorial (https://www.comsol.com/model/modular-mixer-16903), however I am using backswept impeller instead of pitched impeller.

I am getting the error "NaN or Inf found when solving linear system using SOR". I have tried using a fimer mesh but the solution is still not converging.

Attached is the .mph file.

Any help would be appreciated!

Cheers,

Moin