I cant acsess setup of my RNDU4000 Raidrar 4.3.8 Firmwire 4.2.31

So I guess nobody does a forum search before posting the 10th (or more) identical question.

Yes, most browsers have removed support for TLS V1, which your NAS uses.  For Windows users, IE is still an option (though it may need to be turned on).  For others, you'll need to install an outdated verison of another browser (like Firefox) and set it up to never update.

Your Ultra4 is upgradable to OS6, which supports more modern browsers.  There is a special procedure for doing so (which can be found with a search, though I recommend using Google, not the forum search).  Doing so wipes the drives, so you'll ned a backup, and 2GB of memory is recommended for it.  If you intend to use the NAS for a lot longer, I highly recommend you make the switch.