Unable to change the frequency of the model due to some error

Hi guys,

I need some help regarding some kind of error message received, I had been doing the modelling regarding the heat radiation of a cell phone and wireless router to the human head/body. I am currently using the model that is already available inside the Comsol library, and whenever i change the frequency of the cell phone (PCB board) ) more than 2.3Ghz, there is a error message as shown below,

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Undefined value found.
- Detail: NaN or Inf found when solving linear system using SOR.
- Feature: Stationary Solver 1 (sol1/s1)
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Does this mean that I can't do the simulation with a higher frequency? I have search the web regarding similar problem and the solution i gotten is to change the mesh size to a finer size. But after i try it, the same error still pop out.

I really appreciate if someone can help to share their solution over here, so that others who have similar problem can learn.

Regards,
Boon Heng