Sorry! Free domains with extensions such as .tk, .cf, .ml etc., are not supported

Hello,

I am getting this error message when I try to add domains to the list.

Please note that I want to add several domains.

Now, I added these domains yesterday and it worked, but i did not finish verifying them. When I came back today to verify it told me that the service is not available. When I deleted the domains and tried to add them again I got this error:

Sorry! Free domains with extensions such as .tk, .cf, .ml etc., are not supported

All my domains are .com or .org so they are paid domains.