Url format in Chicago 15 Style

I’m formatting my PhD thesis in Chicago Style 15 A. When I create a reference the format allows for a url address and a “date accessed” entry…so far so good. But when I insert the citation it surpresses the url in both the footnote and the biobliography. Does anyone know how I can overcome this and get the url to print in the thesis (like the style manual says I should)? Thanks in advance!