try to estimate the support stiffness and then use the elastic support to see what a little give might relieve it by.
The stress you are looking at looks in the png like it might be at a sharp interior corner. If so, this calculated stress has no physical meaning and is telling you nothing. In that case, you will have to come up with a more sophisticated way to analyze this. You might, as a shorthand, look at the displacement and see whether it qualitatively seems ok.