Web sites lose SSL certificate bindings on Office Online Server

Note

Office 365 ProPlus is being renamed to Microsoft 365 Apps for enterprise. For more information about this change, read this blog post.

Symptoms

Consider the following scenario:

  • You bind web sites in Internet Information Services (IIS) by using an SSL certificate.
  • Office Online Server is running on the server.

In this scenario, when the server is restarted, the certificate become unbound from the web sites. This issue also sometimes occurs randomly. You can see this issue by viewing the bindings in IIS Manager.

Cause

This issue occurs because the certificate doesn't have a unique Friendly name field. This field is required by the Microsoft Office Online. Therefore, Microsoft Offices Online manager removes the bindings.

The Friendly name field must be unique within the Trusted Root Certificate Authorities store. If you have multiple certificates that share a Friendly Name field, the farm creation process fails because the New-OfficeWebAppsFarm cmdlet can't know which certificates to use.

Resolution

To fix this issue, make sure that the certificate has a unique Friendly name field.

References

Plan Office Online Server