Cannot log into mapped site with admin account

Sites in my network that are subdomains of the main site all work as expected. : (main network)

Sites in the network, but mapped to their live domain: for, logins are not getting in. is a mapped domain in the network. The only user on is admin. This admin account is the super admin account of the network. Trying to access the dashboard of from within the redirects to login prompt, but the admin account fails to log in.

I am sure there is a simple answer but I am stumped. Any help would be appreciated.