I was tried to renew the Certificate by using New -ExchangeCertificate | FL in EMS. After I get the new one, i trried the remove old one, but accidently, i deleted the #3 in the following( i should deleted #2 instead) so, now #3 in gone, while our user open outlook, they always get a message from "mail.abc.com" ask fro a site security certificate and said that the Name of the Security Certificate Is Invalid Can one how how to fix this problem. #1 AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule, System .Security.AccessControl.CryptoKeyAccessRule, System.Securi ty.AccessControl.CryptoKeyAccessRule} CertificateDomains : {vffserverb, vffserverb.abc.com} HasPrivateKey : True IsSelfSigned : True Issuer : CN=vffserverb NotAfter : 3/15/2016 1:27:41 PM NotBefore : 3/15/2011 1:27:41 PM PublicKeySize : 2048 RootCAType : None SerialNumber : A4206B6AAC46E29E4FB348C84B888250 Services : SMTP Status : Valid Subject : CN=vffserverb Thumbprint : 1101EFAEA10D0BB7A3B40DDC5E7C072CC67D27D7 #2 AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule, System .Security.AccessControl.CryptoKeyAccessRule, System.Securi ty.AccessControl.CryptoKeyAccessRule} CertificateDomains : {vffserverb, vffserverb.abc.com} HasPrivateKey : True IsSelfSigned : True Issuer : CN=vffserverb NotAfter : 4/8/2011 8:56:56 PM NotBefore : 4/8/2010 8:56:56 PM PublicKeySize : 2048 RootCAType : None SerialNumber : CD5515C8F79341BA49E51C1002E8D26D Services : SMTP Status : Valid Subject : CN=vffserverb Thumbprint : 0810378DD29E706961D74FC8978578B84038EFD8 #3 AccessRules : {System.Security.AccessControl.CryptoKeyAccessRule, System .Security.AccessControl.CryptoKeyAccessRule} CertificateDomains : {mail.abc.com} HasPrivateKey : True IsSelfSigned : False Issuer : CN=Network Solutions Certificate Authority, O=Network Solu tions L.L.C., C=US NotAfter : 9/7/2013 4:59:59 PM NotBefore : 3/14/2010 5:00:00 PM PublicKeySize : 1024 RootCAType : ThirdParty SerialNumber : 00DA21248FD4D56A3B62F9320A59538246 Services : IMAP, POP, IIS Status : Valid Subject : CN=mail.abc.com, OU=Secure Link SSL, OU=Secure Link SSL, O=abc, STREET=XXX, STR EET=XXX, L=XX, S=XX, PostalCode=XXXXX, C=US Thumbprint : 5097C294E40C7892943F3396B15EC143B20DE135

Unfortunately when you did the remove-exchangecertificate it removes it from the local certificate store. Do you have a back up from when network solutions first emailed it to you? Do you have another CAS server that you can copy the cert from? If you don't have either than you will have to request a new one.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com

Hi beidog, Any updates?Please remember to click Mark as Answer on the post that helps you, and to click Unmark as Answer if a marked post does not actually answer your question. This can be beneficial to other community members reading the thread.