New registrations not working

I am running J! 2.5.1 - PHP 5.2.9
I have re installed CB v1.7.1
I have re-read all documentation I can find.

The problem:
when a new visitor wants to register using the CB Login [ index.php/component/comprofiler/registers ]
the CB system will not recognize any email address other than email on my server. I have tried a number of known, working email addresses to no avail. I activated the AJax email checker and the same problem. If the email is on my server, it will send the email messages, however, if the email address is NOT on my server, then the Ajax checker displays "Could not check this email: Please double-check: Needed for confirmation"

Your help is greatly appreciated.

This can be tested at Mark4.com/blog.

Kendall

Turn off the Ajax checker if you do not want such messages in frontend.

It is just a warning stating that the system cannot verify the the email address actually has a mailbox on the other end.