Domain Mapping is not working.

Hi ,

I have a Wordpress multisite and i am having trouble with one of the domains. The client contacted me that he could not see his website,
I took a look at the domain mapping plugin and it said invalid in red letters, so i went ahead and updated the domain mapping plugin to the latest version. But now i cant map it anymore i get an error message that says Domain Name is invalid. i checked the domains IP address and its pointing to the correct IP.

Any ideas why this happening? Please help.

This is the link network link:
and this is the main domain it should be mapped to:

Thanks in advanced.