Unable to Create Solid

UnabletoCreateSolid.3dm (156.2 KB) Hi,
I am fairly new to Rhino, and I have been successfully using the CreateSolid command for a few days, but when I tried it today, it just doesn’t work, even thought I am using the same file, with almost identical surfaces. Rhino does not give a reason for it. The objects all intersect, so I quite sure I have made the objects correctly.
Any advice would be appreciated…
Update: Uploaded file, and I tried rebooting my laptop (I hadn’t done that for a week), and it still does not work.
Thanks

Without a file it’s hard to give you advice here…

I’ve just uploaded it…

Several of the surfaces do no intersect. CreateSolid requires intersecting surfaces. CreateSolid | Rhino 3-D modeling

To find where the surfaces do not intersect:
Make a layer other than Default as the active layer, preferably with a different color.

Intersect

SelSrf to select the surfaces.

Inspect the results of Intersect. There will be curves where surfaces intersect and no curves where they do not intersect.

Fix the surfaces so that they intersect. You can use ExtendSrf.ExtendSrf | Rhino 3-D modeling

Thanks - I extended the sides over and above the top and bottom surfaces and retried it, it works now.