Updating exchange certificate
Sometimes this certificate is not generated properly or not replicated to all Exchange servers.
When this happens, applications such as Office Online Server (OOS) will not view attachments in Outlook Web even when OOS is properly setup and configured.
The process for creating a new Server Auth certificate is simple and generally does not cause issues for Exchange UNLESS you are integrated in a hybrid Office 365 environment, or have integration with Sharepoint or Lync that utilizes OAuth.
If you are, make sure you understand the impact of replacing this cert with those services.
This is because all these services are in IIS under same default website. Similarly, POP/IMAP and SMTP can also use same or different digital certificate. Domain names to be used internally and externally has already been planned. Digital Certificates are used to secure communication between clients and servers using SSL protocol. This is the server where certificate request will be stored. Here, you can specify which domain names to be included in the certificate.