If you do not create a Menu and assign its Location eg. Primary Navigation, then WordPress automatically displays All Pages in its place. To fix the issue you must create a menu and set its location to the Primary Navigation.
Thanks, I have done the changes and it helped. However, I still have issues with mobile view, it seems I can not make the menu off-canvas. Please check it out. plasmart.hu
I have custom off canvas menu enabled only for mobile.