Gap at Intersection on Edge FIllet

I am trying to edge fillet this structure. I keep getting a gap at the intersection. I get a gap like this even when I specify the corner edge or not; and when I set the fillet radii very tiny.

If I fillet the corner on its own, it looks like the sides pull way from the top.

Is there a simply way to solve this?

Could be a number of different causes. Upload a file with the geometry if possible.

My guess would be that the two surface edges have differing angles. That makes it really difficult for Rhino to generate the joining intersection. Try making both edges the same angle since you’re filleting them. Or fillet in the corner first and allow the fillet to flow smoothly.

I stumbled across a solution. Here is the model in wireframe.

This morning, I was wondering if the redundant edge was causing the problem. I discovered the MergeAllFaces command.

Then it fillets fine.