Why can’t I add a new name that uses a hotmail.com address?

I am trying to add a new contact in Windows Mail who has a hotmail.com address. Each time I get the following error message - "The contact information could not be saved. Check the contact's information and try again"  The contact information is correct because the e-mail arrived in my in-box and I simply clicked on the hypertext ADD CONTACT.  What could the problem be?  Thanks for any input.