Ran Into Problems A Using My RNDuoV2

Dear Forum Members

First, had to use a new registration and email to actually make this post, for some reason I could not use my old info to gain access to this forum.

Anyway, my problem is this:-

I have an RNDuoV2 that now house my 2 x 4GB WD Red HDs, which were originally in my RNDuoV2 bought in 2012, i.e. it died after 14 years. This RNDuoV2 was working perfectly up until one of the recent Windows 11 updates.

Now I have found that I cannot access Plex any more, although my other two RNDuoV2s still work perfectly. However, I can still access the problematic RNDuoV2's Dashboard, thanks to that utility this forum supplied a few years ago but Plex, on this device, is locked away.

As you can see, from the screen print below, The Name is from the failed (2012) original RNDuoV2, which contains part of it's primary MAC address, and IP Address with the MAC address (in brackets) from the recently bought hardware. 

I believe the problem is probably caused by this RNDuoV2 now has two MAC addresses, one from the original failed device, i.e. this number is embedded in HDs, and the second MAC address is part of the new (old stock) RNDuoV2's hardware that is now housing my original HDs.

So I'm guessing that if both MAC addresses can be consolidated into one then the problem would go away. 

Is this possible?

My next thought is hoping that there is a utility or script, probably something that can be placed in the Plex icon, that can work to reacquire my access  to Plex.

I get the following error message, and similar messages from other browsers (as seen in the attachment), when ever I click the Plex icon or type the URL directly into my other browsers.

Hope someone has a solution or, failing that, a suggestions that may work, and as before any questions, query or clarifications required will be answered asap.

Cheers.

UK Bob