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]