Whoops! I evidently did not say things well.
I had cameras on two networks. One being my LAN (192.168.1.x) and the other the 10.1.1.x contained within the NVR.
The issue is that the computer with the BI on it ( Lets call it the BIBox) is on the 192.168.x.x network. It has no direct contact with the 10.1.1.x network.
The NVR has contact with both networks. Both for cameras, and for the NVR Web GUI on the BIbox. Accessing the NVR through the Web GUI on the BIBox, I use 192.168.1.250 in the BIBox browser to access ALL the NVR cameras feeds, that it gets off both networks. Indeed, you showed me how to specify camera number.
THANK YOU again!! And those feeds were sufficient for BI use.
BUT... I needed access to the actual Web interface of the camera itself. I was adjusting variables that were not available via BI or NVR menus.
So I needed to use a browser (Edge, Chrome) , and directly interface with the camera. Easy peasy with the 192.168 cameras. But... the cameras listed with a 10.1.1.x address were the issue.
Sure, I can access the NVR via 192.168.1.250 from the BIBox.
And when I do so, and go to Camera Management, I can see the IP addresses of all the cameras.
And, as I said before, Can click on the "IE" icon and it opens up the Web Access page for that camera...
IF it's on the 192.168.1.x network.
The ones on the NVR POE ports are on the 10.1.1.x network contained within the NVR.
Click on the IE icon by them, and it opens up the Web Access page for that camera.... Or tries. Fails to connect.
The NVR is putting the address of 10.1.1.x into the browser bar of the BIBox - that has no access to the 10.1.1.x network by itself.
ONLY Via the NVR .
So I end up with the BIBox not being able to connect to the 10.1.1.x networked cams directly. Because it is on the 192.168.1.x network.
That was where I was stuck.

I sincerely hope that is a bit better explanation.
I had no way of accessing the Web GUI of the cameras, plugged into the NVR POE ports, from the NVR menu that was offering them to me.
I would have thought that if the NVR is giving me access, showing me addresses and offering me a direct link ..... that the link would work.

NOT to say it is an AMCEST issue!!

It VERY well could be me!!

Often is!
If anyone can figure it out, I have faith in you.

And perhaps we can help another searching soul down the line.
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But it is what it is, don't like the NVR you said
ok, ok... 'inadequate junk' was rather harsh.
SORRY AMCREST!!
I was rather frustrated at that time.
Its not junk. I hope to use it as a NVR/router/POE source for my barn and north gate cams. But as far as a stand alone home security alternative to a computer running BI... inadequate is a fair word. (Power usage aside!)
And IE has been "dead" since '22. I would not expect NVR's sold years later to still rely on it for feature access. Just my 2c, not a judgement.
THANKS AGAIN for all you do, and for going through the frustrations to educate people. You ROCK Sir.