“Show as expanded” selected but children menu items not displaying

Question

I've main menu navigation and some links checked "Show as expanded" and have child items under it. In the main site page, only parent items are appearing and child items not appearing. I've created a twig template "menu--main.html.twig" and kint the item and found that "is_expanded" is FALSE and there are no child items.

Answer 1

I've solved it. I've figured that I should have to configure the block and extend the menu levels