Help with mesh building for a simple 2D geometry

Hi,

I was working on a model that couples the physics module Phase transport in porous media and Darcy's Law together. In Comsol Application Gallery, there's an example ' Wicking in a paper strip' where the width is constant. I was trying to study the 2D effect of this process, so I changed the geometry. But there's always error occurs, I'm wondering if it's the problem with my mesh.

I've attached two screenshots, one is the example from Comsol (paper strip), the other one is the mesh I built. Could anyone take a look and let me know whether this mesh looks appropriate?

Thanks a lot.

Jing