Difficulty in simulating simple H-Cell

Dear All

I m new to comsol. I started to design a very simple H-cell as demonstrated in Video

www.comsol.com/video/video-239

But when I try to simulate i get this error:

Failed to find a solution.
Maximum number of Newton iterations reached.
Returned solution has not converged.
Can anyone help me in this regard..I did exactly the same way as demonstrated in video.Pls help

Regards
Yousuf