Mega Menu is displayed but not allow to select items. Desktop / mobile

I′m responsible for the maintenance of the site
consigueunasmartv.com.

I haven’t had much trouble so far. this site works with the
Flash theme and has the max mega menu plugin installed. All the plugins are in the latest version.

The problem is that since the last update of the theme (it has a child theme) the max mega menu in the desktop version and also in the mobile version is shown but it does not allow to select any item under the second category of the submenu “televisions” for the version of desktop; in the mobile version it does not allow to select from the third category of the menu and only the first category of the submenu “televisions”

I guess from the recommendation of the plugin: https://www.megamenu.com/documentation/removing-residual-styling/ this is due to the residual styles of the theme.

I have followed the steps indicated in the documentation. I removed the HTML, that is in the header.php file through cpanel, from <nav id = “site-navigation” class = “main-
navigation”> to </span> (it’s 5 lines) covering
<?php
wp_nav_menu(array(
‘theme_location’ => ‘mainnav’,
‘menu_id’ => ‘primary-menu’,
‘container’ => ‘div’,
‘container_class’ => ‘menu’
));
?>
But it doesn′t work.

I have also read this thread here: https://www.ads-software.com/support/topic/first-6-menu-items-work-and-then-they-dont-after-that/

I’ve added the indicated CSS lines:

.site-header.default .main-navigation {
z-index: 99999999;
position: relative;
}
both in Appearance> Customize> Additional CSS in wordpress and in Mega Menu> Menu Themes> Custom Styling in the customization of the plugin.

But nothing. Any other CSS suggestions? or something else I can do?

regards

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