Visual Composer Not Loading

Hello, We purchased the theme and Visual composer is giving us a mixed content error and it is not loading. Mixed Content: The page at ‘https://www.oursite.com/wp-admin/post.php?post=23605&action=edit’ was loaded over HTTPS, but requested an insecure stylesheet ‘http://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,600italic,700italic,800italic,400,300,600,700,800&subset=cyrillic,latin,greek’. This request has been blocked; the content must be served over HTTPS. How do we resolve this?