If Ranger Remote is set to connect using WSS, Firefox will fail if the
SSL Certificates (installed during Ranger Remote installation) are not
installed properly within Firefox.
Firefox does not use the Microsoft
Cert Store like Edge, I.E., or Chrome. SSL Certificates must be
imported to the browser directly. This is done by the Ranger Remote
installer.

If Firefox was installed after Ranger Remote was installed, the SSL Certificates will not be installed into the Firefox browser.
To verify your Silver Bullet certificates are properly installed, check the Firefox Certificate Manager: