AnnaPepe

I already wrote that I have the latest version of the theme and that are not the plugins!
what could be the problem since it is also present on the demo?

I solved, I identified the exact code, thanks for this super theme

.nav-collapse.collapse, .no-navbar .nav-collapse {
    background: rgba(255, 255, 255, 0.97);
}
.tc-hover-menu.nav a {
    border-bottom: 0px solid #fff;
}

solved here
https://wordpress.org/support/topic/all-in-one-seo-help-4?replies=5

the majority of SEO plugins will try to find which page has been registered as the front page in your database options with get_option(‘page_on_front’).

When choosing “Don’t show any post or page”, no specific page is registered as front page, meaning that it won’t be found by any plugin.

Two possible solutions to this problem :
1) Workaround : define an empty page as your front page and then optimize its SEO options with your plugin
2) Do it yourself : hook in the WordPress function to add your custom SEO options, for example, the site title can be modified with wp_title hook. You can also add meta tags by hooking into the wp_head hook.

Hope this helps.