I have an error when meshing.
 

I am trying to mesh a heat exchanger however when I am meshing I get an error message saying that:

Possible Cause: Very sharp angles bewteen adjacent surface triangles (i.e. dihedral angles near 180 degrees).

Connectivity Error: Failed constructing consistent topological regions. See output window for additional details.

Can any one give me a reason why this might be happening?

I am a fresh man in Star CCM+, but i wonder the problem may be lies in:
1. are there any holes or very sharp surfaces on your geometry?
2. whether the region is a single domain that the fluid will not "leak" somewhere?

This error will be followed by a list of points. Go to that portion of the geometry and see what the problem is.

This can also happen if the base size of the mesh is too big. In the navigation tree go to Simulation -> Continua -> Mesh -> Reference Values -> Base Size and reduce the value in the property window.