Internet Security Warning

Using Windows 7 Live Mail, I get the following message/pop-up after my emails are received "The server you are connected tois using a security certificate that could not be verified. The certificate's CN name does not match the passed value. Do you want to continue using the server? Yes NO"  When I click on YES, the pop-up disappears. If I click on NO, then I get the pop-up every time I get another email. Can somebody solve this problem?
Thanks for your help,
Bob W.