Unable to set HTTPS server certifcate for admin access

Description

This article describes an issue where the HTTPS server certificate is not being displayed.

Scope

FortiGate.

Solution

The certificate for administrative access has been successfully uploaded to the FortiGate. However, it does not appear in the HTTPS server certificate selection list.

Certificates can be uploaded from the FortiGate GUI by navigating to System -> Certificates -> Create/Import -> Local Certificate.

Local certificates are used by the FortiGate to identify itself or the services it provides, such as HTTPS administrative access.

This occurs because the certificate includes Client Authentication in the Enhanced Key Usage, whereas it should include Server Authentication for this scenario:

To resolve this, get the certificate with Enhanced Key Usage as Server Authentication:

Import this certificate with Enhanced Key Usage as Server Authentication in firewall so it will be available in the HTTPS server certificate list: