Federico Alzamora Previtali

It's hard to tell from your screenshot, but there might be a few cells that are not of good quality. In your Outline in Meshing, click on Mesh > Quality. What are the Min/Max values for Orthogonal Quality? What about Skewness?

Alternatively, if you do a Mesh Quality check in Fluent, what is the reported Minimum Orthogonal Quality?