To Renew new certificate in Exchange servers we need to remove the existing the certificate and import new certificate.

1.      Open Exchange Management Shell buy doing run as administrator

2.      Type Get-ExchangeCertificate |fl| out-file –filepath c:\certs.txt

3.      C:\certs.txt will have the details of the current certificate, need to make a note of “Thumprint” of mail.domain.com

4.      Type Remove-ExchangeCertificate  –thumprint <thumbprint>

5.      Confirm to remove the certificate

6.      Import-ExchangeCertificate –path “Certificatepath” –FriendlyName “mail.domain.com”

7.      Enable-Exchange Certificate –Thumbprint  <thumbprint> -Service IIS

8.      Enable-Exchange Certificate –Thumbprint  <thumbprint> -Service pop

9.      Enable-Exchange Certificate –Thumbprint  <thumbprint> -Service imap

10.  Get-ExchangeCertificate  | fl to display new certificate details