The sketch or filling face can't be extruded

I’m fairly new to Shapr, however have used CAD programs before, although I’m a little lost on this one.
I’ve imported an DXG from Illustrator, and most of my faces will extrude.

This one however (and a few others) simply won’t. As far as I can tell, the face is complete and there aren’t any gaps in the edge. I can also extrude the face on the outside of this face without any issue

Any suggestions as to where I’m going wrong? I’ve read from other posts that importing DXG’s can sometimes leave breaks in the lines, but as you can see, I can select the face (suggesting no gaps) without issue

Hello ghesp,

You can try “lifting” / moving the “D” off of the present sketch plane, by a very small amount. (Creates a new sketch plane). Then try too extrude again.

This is what I usually do.