To troubleshoot, follow these steps:

  1. If you use Firefox’s current release, verify that the option to Allow Firefox to automatically trust third-party root certificates you install is enabled. For more information, see Automatically trust third-party root certificates in the official Firefox documentation.
  2. If you use an ESR version earlier than 120.0.0, make sure that you enable enterprise root support. For more information, see Setting Up Certificate Authorities (CAs) in Firefox in the official Firefox documentation.