Embeddable not visible for text editors with custom contentId

After creating a new embeddable in Embeddable studio, I have made its availability everywhere,

But For custom content types, the embeddable is not being accessible when we create a new text editor using the following code,

$core_v2_editor.Render('body',"%{Width='100%', Value='$!contentBody', ContentTypeId=$contentTypeId}")

I want to make the embeddable be available in this custom content type so that it renders in the text editor.