I am attempting to wrap a lofted boss with an elliptical outer surface around the casing in the attachment. The end profiles for the lofted boss are planar surfaces and there is a guide line at the center of the outer surface and another directly opposite it on the inner surface. I had started to create several profiles, but I assumed that, with guide lines, only end profiles would be required. There is some intermediate construction, but I believe that I have turned all of it into centerlines so it should have no effect.
When I attempt to create the lofted boss, I get the ever-popular "Lofting operation failed to complete" error. There is no preview of the lofted boss. I have tried to find unwanted entities in the sketches and adding two more guide lines at the edges of what would be the inside loft surface if this can be persuaded to work. This seems like a pretty simple lofted boss with little room for a problem to hide in.
The file is attached. Please note that, once this has been solved, I intend to exrtend the thinner end of the lofted boss to an extremely shallow profile that is located at the 12 o'clock position at the top of the casing. It barely shows on the image, but it will be found on the part.
Thanks for looking!