Error creating a flat pattern for a simple component with contour flange

[gerardp5PM5L]

Hi, a very new user to the sheet metal space here.

I'm trying to create a very simple component in sheet metal with one curved surface on it.

I can model it fine but when I try to create a flat pattern Fusion 360 gives me an error with no text...

Does anyone how to go about solving this?

Thanks in advance!

[gerardp5PM5L · Accepted solution]

OK, I just tried this again in a new design. Almost identical steps recreating this component with only one flange being placed at a different location and now it works. I don't understand it but I'll take the win.