Cannot print my 3D model

Hi all,
I am new to 3D design/printing and am stuck trying to print this design.

My 3D slicer does not seem to recognize this as a printable design. I expected the slicer to fill in the hollow chambers, giving it its shape.(you can see the inside in the screenshot below)
Anybody know what I am doing wrong and how I can fix it?
Laser add on.stl (3.3 KB)

Main issue is you have 7 stray edges at a distance within your component. Remove them. Also the whole thing is inside out, reverse the faces so it is all white on the outside.
I have used a plugin to remove the triangulation that is created by the stl, if you have your original model removing the edges and reversing the faces should work.
GIF 16-05-2024 6-29-57 PM