I need some help figuring out an issue I'm having with Umbraco Forms generating a content page.

The problem: I've created a content page and setup a form with various text boxes and a dropdown field with prevalues set from a data type I created with a dropdown list of 'categories'. I mapped the form fields to the content page fields and have set the location to save the content page to. When I test the form and submit it, all the fields map with the content added in the form, except for the dropdown 'categories' field which remains blank.

Has anybody encountered this issue before and might somebody be able to help me come up with a solution to get this to work?