Hi there,
I tested the code on my local installation and it shows the form with no problem:

Please go to the Cornerstone and add a Classic Raw Content element and paste the HTML code there and save the page and you should see the result correctly on the front end of the page.
In general, I strongly suggest that you use the Contact Form 7 plugin instead as it has more security features when it comes to the form submission.
If you still have problems please follow the steps below:
- Ensure everything is up to date according to our version compatibility list here. Please follow the best practices when updating your theme and plugins. Click here for more information.
- If you’re using a CDN, please clear the CDN’s cache and disable optimization services.
- Test for a plugin conflict. You can do this by deactivating all third-party plugins, and see if the problem remains. If it’s fixed, you’ll know a plugin caused the problem, and you can narrow down which one by reactivating them one at a time.
- Remove custom CSS and Javascript from the options or Child Theme and test the case.
Finally, if you still need our help kindly get back to us with the result of the steps above and URL/User/Pass of your WordPress dashboard using the Secure Note functionality of the post to follow up the case.
Thank you.