Can′t create submenus

Hello everyone! I′m posting here since I haven′t found a solution for this issue in the forum.

I′m currently working on a site ( https://mrdsoluciones.com.ar/ ), hosted by Hostinger and with the Neve theme active.

I can′t seem to create subcategories for my Main Menu. Although I′ve placed the secondary items under the primary ones and to the right, the landing page will show them like they′ve all got the same hierarchy.

Here′s how it looks:

How can I fix this?

Thanks in advance!

The page I need help with: [log in to see the link]