Osnap ? Not snapping

If I build a box from lines, make surfaces , then join. Move the joined surfaces over and want to osnap a line to the midpoint of an edge, osna does not respond. Had me wondering if something is wrong. Any thoughts would be a help. Thanks,Mark
I have to be retrained so often

The Midpoint osnap should work on surface and extrusion edges if you are within 15 pixels (default osnap radius), of the actual midpoint of the edge

If you have an example of something where that doesn’t work, please attach it to a reply.

Hi John, I opened a new file and did same routine as previous explanation and works fine, so must be in the other file I am working in.
Reopened explanation file and still not able to snap to any of the surface edges hmmm
All though will snap to any curve in that same file

Is the object a long way from the coordinate origin?

126" from 0,0,0 in an inch file

Can you send us the file?