There are always different methods to create the model, in this case, one set of the offending curves needs to be redone. The following method redraws the horizontal curves as the radii you’ve used are a fixed size.
Explode horizontal polycurve and delete the right hand line with it’s two fillets - which are 8 units radius each, so easy to redo.
Flip CPlane to Right,
ExtrudeCrv the left line to create construction surf,
Split the angled lines with that surf then delete the surf,
Draw 2 new horizontal lines to the newly split line end points,
Fillet the new horizontal lines with the existing at 8 units radius,
Using a combination of 0 Fillet, Join and split on new horizontal as req’d to create the wires to build the surfaces.
As a check, all the various construction curves should be able to 0-radius fillet with each other, then you know your input curves are tight before applying surfaces and you know you will be able to join the surfaces into a good polysurface.