Try one of the following:
1. If you are using any caching plugin (like "W3 Total Cache" or "WP Fastest Cache"), then don't forget to delete the cache before seing the code printed on the website.
2. Make sure the code is in <strong>Published</strong> state (not <strong>Draft</strong> or <strong>in Trash</strong>).
3. Check if the <code>wp-content/uploads/custom-css-js</code> folder exists and is writable