Receiving windows login prompt when trying to access login screen

Receiving windows login prompt when trying to access login screen

I am in the process of setting up ADSelfservice Plus to be available outside our firewall and also enable MFA for Exchange.  I have installed a wildcard SSL and everything looks good, except when attempting to access the login page it brings up a windows login and password screen first. If I close the window entering nothing, the ADSelfservice login page then loads. This can be avoided by adding the external site to trusted zones on their local computers but I can't expect our users to do that. I know it's probobly something simple, but I do not know what.
                New to ADManager Plus?

                  New to ADSelfService Plus?