Add New Isn't Working Correctly

When I click the add new button it goes to a front end page of my site with nothing but the header and footer showing.

This is the URL the add new goes to.
http://mysitedomain.com/wp-admin/edit.php?post_type=cmdm_page

I have permalinks set to “Post Name”. I can’t get to any admin page when clicking the add new button. Any suggestions?

https://wordpress.org/plugins/cm-download-manager/