We have a SBS 2003 for our small office. The original problem was that the computers were loading slowly so I changed the DNS configs to point to the SBS (DNS server). Now the computers load quickly. Welllllll, when I try to access the company website from the office, I am prompted for a Username and Password, which is not needed. I Viewed the certificate from the error message and saw that it was using our OWA certificate. When I remove the DNS settings, the computers go back to loading slowly but they can access the company site with no problem. For example, company domain "Thanks.org", OWA is mail.thanks.org and website is thanks.org.
I went to redo the certificates and saw that the CA wasn't installed but there is a Microsoft Certificate for the OWA. I installed a certificate for thanks.org but it still did not work.