Problems trying to run ReadyNAS Duo V2 with Firefox and Windows 10

After trying unsuccessfully to run my old ReadyNAS Duo V2 and use it for sharing pictures, I shelved it again for future consideration. I posted a thread here about 10 - 11 months ago and got nowhere with my device.

Future arrived a few days ago. I have the need for multiple computer home backups, so thought I would get after this thing again.

I know it is an old piece of hardware and there are many newer models that likely work better, but I really do like this thing, it is paid for and it's mine. Sticker on the bottom says Product Number RND2000-200NAS. Model No says RND-2B. Front of unit, bottom right says ReadyNAS Duo v2.

I am running 2 - 2Tb drives in a RAID1

If I can only get it working properly.

Couldn't remember my password etc, managed to get into it via the RAIDar Browse button, saw there was nothing I needed, did a factory reset and started over. I set it all back up again. Thats when the problems really hit me.

I run the latest version of FireFox. I type my home network address - 192.168. etc and I am greeted with:

Secure Connection Failed

An error occurred during a connection to 192.168.0.25. PR_CONNECT_RESET_ERROR

The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
Please contact the website owners to inform them of this problem.

I have spent nearly the whole weekend fiddling around with it, trying to get around this stupid error. I have come up blank and cannot figure out what this error actualy means.

I think it has to do with a certificate being invalid or no certificate or some fool thing like that.

I pick up my Samsung tablet, type in the address, and I am in. No problem. No errors, no blocking me at all.

I launch MS Edge, which I do not like and do not use, but it will let me in by clicking my life and title to my first born away - In other words, there is the option of proceed anyways and click 3 or 4 warning messages away. When the browser opens, it has a big Unsafe Site message at the top.

Most of the stuff inside the device menus is blank. I cannot do much with it. After several shutdowns and reboots of the device I have managed to get into it via MS Edge and my windows File Explorer. Dumping a buch of files on it now to play with it.

I know that with all the safety breaches, security challenges and all that going on that browsers and more have tightened up things so much that older hardware simply won't run, but surely there has to be a way to properly run this device....

Can anyone guide me on how to get around the browser errors?I cannot afford to fork out hundreds of dollars for a new NAS.

Thank you