Just one last thing to wrap up my last comment:
To solve the issue with the convergence, you can apply the workflow provided by this tutorial. That problem seems to be caused by the low quality of the generated mesh, which in turn happened because of some unwanted features of the CAD model, as I mentioned. In order to inspect your mesh quality, take a look at this tutorial.
Take for example, the volume ratio of your mesh, which is outside the ideal range:
Following the steps provided in the first tutorial, you will notice that it is interesting that the trailling edge of the airfoil is cut (such as here), so that the mesh for the boundary layer is more comfortably generated. In your case, your edges are sharp, which makes the generation of mesh around it difficult.