Did a little research and found that the menu adds the scrollTo class to all menu items regardless if they are on page or not and then this code gets added, which leads to “regular” links that point away from the home page being unusable.
If you want to add an external link to the menu, you have to follow the next steps::
Create a custom link in the page Appeareance > Menu
Load the website and copy the ID of the menu link. You have to read the source code to get it.
Go to the page Appearance > Theme Options > Custom Scripts, and type the next code in the option Custom JS. With this code you will disable the function ScrollTo for this link: jQuery("#menu-id").removeClass("scrollTo");