Domain mapping to sub folder site - invalid error

I installed WP 3.9.2
I installed WP multisite with sub folders
I installed WP Domain Mapping plugin and activate it
7 sites are manage wih WP multisite

I want to point these 7 domains nams to these 7 site. Everytime I enter a domain name in the Domain Mapping admin I get an "invalid" error message.

Thank you in advance and best regards.