When I click on 'Map Domain' nothing happens

Everything is set up as it should
dedicated IP: YES
dedicated IP opens website
sunrise.php moved to wp-content folder
'A' record of domain set to IP address of multisite.
wp-config is setup properly
Am I missing anything?
Anyway, I go to the site I want mapped and I enter the domain, click on the 'Map Domain' button and the gif animation comes on then goes off and nothing is mapped. The input box remains empty after I click on Tools>Domain mapping.
Meanwhile when I try to access the domain it redirects to the main mutlisite which confirms the 'A' record is working as it should...its just not being mapped at my multisite. Please advice. Thanks