Having trouble creating child theme from Ever After

I’d like to create a child theme based on ever after however I am getting an error message.

Broken Themes
The following themes are installed but incomplete. Themes must have a stylesheet and a template.
Name Description
ever-after-child The “ever-after” theme is not a valid parent theme.

Is it not possible to create a child theme since ever-after is a child of the forever theme, and one cannot create a grandchild theme?

Thx for your help