Multisite: menus can’t be added in child sites

It seems that we cannot add menus in child sites in multisite. Did anyone face this issue before?

I have the Menu container enabled in my functions.php

register_nav_menus(     array(         'primary-menu' => __( 'Primary Menu' ),         'secondary-menu' => __( 'Secondary Menu' )     ) ); 

I can add menus to the parent site. But I can’t do it in the child sites even though I can see the Menu container and the Create Menu button.

No menu is created when the Create Menu button is clicked. WordPress just refreshed the page and the menu I tried to create is not present at all.

I have inspected the database of my child site and I can’t find any row for nav_menu_item.

Any ideas?


I also found out that I cannot add any category or tag in my child sites. Why??