Instead of CourseGrid Addon you can try below post snippets shortcode –
[show_post_snippets layout_class="rounded-images" post_type="sfwd-courses" number_of_columns=3 post_count=6 image_size='medium' excerpt_count=100 display_title="true" display_summary="true" show_excerpt="true" hide_thumbnail="false"]
ie, you need to give post_type parameter value as “sfwd-courses”.
Pls go through Post Snippets Shortcode in themedocumentation inorder to know more about shortcode parameters.