Hi, Have an issue with a Go Daddy issued certificate for my exchange 2010 server, server is called: exch2010.company.local. The certificate has the following subject alterneate names: webmail.company.co.uk, legacy.comapny.co.uk, autodiscover.company.co.uk services of IIS,POP,IMAP and SMTP assigned to the new certificate, OWA works as expected. However a migrated Outlook clients will get a pop every time they launch outlook stating the certificate name is different to the server name [i.e. webmail.company.co.uk is not exch2010.company.local]. Go Daddy say they can add the additional name of: exch2010.company.local, by revoking the current certificate and issuing a new one [same thumbprint] However can I import the new certificate [via mmc | certificates | local computer | personal | certificates] over the existing one? Concerned that the original cert request only had 3 names and this cert will contain 4 [or will the certificate not care?] Did start this query in Exchange 2010 secure messaging but was asked to post in "security" when asking certificate questions. Thanks, Fizzmo

this is because certificate SAN extension don't contains exch2010.company.local DNS name. Many applications don't look to Subject field if SAN extension is present. Therefore as a best bractice you should duplicate Subject field to SAN extension.http://en-us.sysadmins.lv

Hi, Thanks for the reply. I have revoked the issued certificate and created a new CSR on the exchange server and am awaiting the new cert with all 4 SAN names. from testing in virtual so long as the "exch2010.company.local" exists as a SAN all is good. Regards, Fizzmo