Sorry, it looks like you may have used the wrong URL!
The correct URL will look something like this: https://somecollege.dualenroll.com
Where "somecollege" would be replaced by the college name used in the college's primary URL.
A few examples:
College of Western Idaho: https://cwidaho.dualenroll.com
LeTourneau University: https://letu.dualenroll.com
Missouri State University: https://missouristate.dualenroll.com
Montgomery College: https://montgomerycollege.dualenroll.com
Jamestown Community College: https://sunyjcc.dualenroll.com
College of Southern Idaho: https://csi.dualenroll.com