Domain Mapping, wp-admin non existent, multi-site, confused!

I'm probably missing something ridiculously simple...but.
Running a multisite - no problems thus far creating subdomains from
within my super admin on wordpress. So I have domain.com and
sub1.domain.com.
Just transferred clientdomain.com to my hosting service. Am using WP
Integration with WHMCS, WP Provisioning and Domain Mapping.
Wordpress added clientdomain.com and mapped domain to
clientdomain.com. However I can't view the dashboard of
clientdomain.com. I'm also using the New Blog Template plugin and am
looking forward to using the template created on sub1.domain.com to
clientdomain.com.
As I said, I'm sure I'm missing something but just can't figure it
out.
Any advice or assistance would be greatly appreciated!