You have a Gravity Form on your page, and it is located below the fold of the page.
Once the form is submitted, the confirmation message is not visible, since the page is refreshed. The confirmation message exists, but it is hidden further down the page.
Once the form is submitted, the page will auto scroll to the form to display the confirmation message. This one line of code is magic.
Add this code to your functions.php file
add_filter( 'gform_confirmation_anchor', '__return_true' );
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