Fillet overlaps itself

I’m trying to fillet an edge, but it wont work. The edge follows an almost oval schape between a bottom uneaven surface and a rib. Instead of connecting all tha way around the shape, the fillet edge overlaps itself and wont connect. I have been trying to split the fillets and connecting them with a blend but then the problem is that the filleted edge is not connected to the rib so it won’t split or trim when im trying to get rid of the leftover surface underneith. My gues tis that this might have something to to with tolerence but not sure how to fix it.

Hi Johanna - please export the object with the edges to fillet indicated as well as the radius, and post the file here or to