Please provide a link to a page on your site where we can see this. Thanks.
Some themes may limit menu depth. A screenshot of what you have under appearance->menus would be helpful, too. Please post the screenshot in imgur.com and paste a link here.
Sorry about that, the website is http://www.hellohomewnc.com and it’s going to be the WNC Guide menu heading. There are already 2 sub-headings under there, but I want sub-headings under those sub-headings. If that makes sense.
Just as a matter of good usability design, going down to a 3rd level menu is difficult for users to navigate. When I’ve had to consider stuff like that, I used a megamenu plugin like this one: https://wpmegamenu.com/
Anyhow, menu depth is a theme thing, so check with the theme’s developers here: https://wordpress.org/support/theme/kale