You can get SSL certificate for exchange server from website www.CACert.org There you can request certificate. They give you certificate in format like:- ----BEGIN CERTIFICATE----- U1GyMdIR/+XOd3deT5eGCo3J8tqg/+ExWaEqQ+Bjls7/+ jnxsDq9rg/6/gzIDOKZLBckoShvn2SaGjJILmo54kP6JU4 YV5QQVDsh/sdfsdfvxtrsdgfgddfgdfg7dfgfdg45dfgdf5g4df/o werert312rtr5e4tret4er5t121g5d45g4df5g 2lFO+AfsdftertbfhfgyfgdgdgdgfgRsFmuZhzdfgdfgdfgqxTd/M= -----END CERTIFICATE----- Save in text file as cert1.cer. Import to CAS Server in personal Certificate store. Now Run command:- Dir cert:\LocalMachine\My fl you will see the currently installed certificate on CAS server. Copy the Thumprint for the newly installed certificate. Now time to enable certificate for the services by running command Enable-ExchangeCertificate -thumbprint 67DA55B9F5AB2A735E7CBD11A895F7757ACC07C4 -services "IIS,SMTP" Replace the thumprint with new certificate thumbprint and enter. You got error :- Enable-ExchangeCertificate : The certifi...