I've been working the navigation menu for my site and have had some trouble with the links. The URLs for the links are correct, but they keep saying "invalid," as you can see in the first screenshot. The second screenshot states "Link is empty." My searches have turned up nothing. Any help?

ETA: When I save the template and view a page, the links do work-- however, I'd still like to know why it gives me this error. Thanks in advance.