Multisite subscribers recieve permission error when signing in.

When I sign in with my multisite test account I recieve the following error indicating that none of my members would ever be able to enter their dashboards:

You attempted to access the "Timeless Metal" dashboard, but you do not currently have privileges on this site. If you believe you should be able to access the "Timeless Metal" dashboard, please contact your network administrator.

If you reached this screen by accident and meant to visit one of your own sites, here are some shortcuts to help you find your way.

My WMPUDEV support is enabled; please take a look and let me know what is wrong.