You have received an RMA SSD with legacy OS 6.5.x. You are unable to access the GUI, as this was to be accessed through Internet Explorer (IE) with the Browser's Java module. IE is no longer allowed & supported in your environment. Edge browser has replaced IE. When you Open the GUI Web Page, in Edge or other browsers, you a blank page where the browser Java applet loads the GUI.
In Edge browser settings, we can customize the ProxySG GUI address to open in IE compatibility mode.
In Edge Browser settings > Default Browser > Internet Explorer Compatibility: Add the page:
https://<ProxySG_IP>:8082/
Restart the browser, browse to the GUI Webpage, now the entire GUI webpage loads with the Java applet on the Edge browser (in IE compatibility mode).
You may now upgrade to the LTR version of the SGOS through the GUI.