Need help with custom shape borders, please!

Hello all!

I’m very new to this and I’m having issues with the custom shape borders. I’ve attached the view of the arch while I’m editing the design- this is how I want it to look. Then once I preview it, the sides of the arch disappear. Not sure how to resolve the issue. Appreciate your help! Thanks!

Window Arch
Window Arch Preview

You need to make sure to group everything and give it all a fixed width.