Menu Diasppearing

Hi,

Suddenly, without doing anything, my main menu and wordpress toolbar disappeared but only when you click on a category or on a single product page.
On the main page the menu is working well.
I also cannot manage to change the underline color of the menu.
When I tried to use not Elementor category template but the theme one, no products appear when you click on a category at all and the WordPress menu and toolbar will disappear again.

Please help, this is frustrating!

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