This beast is quite old and requires an old browser with an old Java to be able to access it.
I used versions from PostableApps, as I do for accessing old Dell DRACs. In particular I used FirefoxPortableLegacy36_3.6.28_English.paf.exe and jPortable_7_Update_51_online.paf.exe.
“Install” them in a temp directory. Firefox will go into in FirefoxPortableLegacy36\ and jPortable in CommonFiles\Java\. Execute CommonFiles\Java\bin\javacpl.exe. The classic Java control panel applet will appear. Heat to the Security tab, enable Java in the browser, pick the lowest security level available which will be Medium. In the past I remember I had to put the https url of my two VNX SPs in the site exception list, but it seems not to be strictly required. Take a look. Close the applet.
Now in the root of your temp dir create a .bat file containing:
set MOZ_PLUGIN_PATH=FirefoxPortableLegacy36\App\Firefox\plugins;CommonFiles\Java\bin\plugin2
start FirefoxPortableLegacy36\FirefoxPortable.exe
Launch the batch file, enjoy.