Can't export variable arabic font

When I want to export my variable arabic font I see this error
What should I do to fix it?

What error? Did you mean to attach an image?

Can you post screenshots of the layers of your glyph sad-ar.init?

And a screenshot of your outlines in your Heavy master?

The red dots mean that you have double nodes. Run “Tidy Up Paths” (Cmd+Shift+T) to delete them.

You need the exact same number of nodes and the same path structure in each master in order for interpolation (and variable font export) to work.

If you select all paths (C,d+A), you will see a litte info panel showing the number of nodes in your current selection. Make sure this is the same in all masters.

Thanks a lot!!!

sorry could you give a picture of the place that shows number of nodes

At the bottom right.
The 50 next to the white box displays the total number of nodes in the layer.
The 50 next to the black box display the number of nodes currently selected.

There is a tutorial about this: Multiple Masters, part 2: keeping your outlines compatible | Glyphs