it says not a rhino file.
Edit: error solved
A solid in Rhino is a closed polysurface. To create a surface from you shape you need to close the open side… Since the open side has four edges you could use EdgeSrf to create a surface. The Join to create a polysurface.
Thanks i did’t think of that even though it’s very simple, thanks for your time none the less!
I was trying to upload a video but you got the solution @maimun2002. I’m little late