Exchange certificate
The Exchange Management Shell cmdlet New-ExchangeCertificate can be used to create a new self-signed certificate or can be used to create a new certificate request, which can be forwarded to your Certification Authority and afterwards imported and enabled for SMTP (Transport Layer Security (TLS)) and/or IIS, POP, IMAP, and UM (so-called Secure Sockets Layer (SSL) services).
To enable certificate use the command:
You can find the certificate thumbprint value by using the Get-ExchangeCertificate
Enable-ExchangeCertificate -Thumbprint 434AC224C8459924B26521298CE8834C514856AB -Services POP,IMAP,IIS,SMTP