Let's start with this;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select Network.

[56+] Type about:preferences#general<enter> in the address bar. Look for Network. +++++++++++++++++++++ Look for Configure How Firefox Connects and press the Settings button. If you are using a proxy, make sure those settings are correct. If there is no proxy, first try No Proxy. If there is a problem, then try System Proxy.

Some problems occur when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

• Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
• Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

https://support.mozilla.org/en-US/kb/configure-firewalls-so-firefox-can-access-internet Configure firewalls so that Firefox can access the Internet.

Tried all proxy settings and nothing worked.

Configuring firewalls so's firefox can access the internet is redundant as it is what is accessing the internet and talking to you right now.

 Just now got a connection to it via Foscam's software (all browsers shut down)  and was able to configure the camera.

 I configured it for my wifi point - which is on a different subnet and therefore, I think, it won't be able to connect?  Router doesn't appear to see it anyway.

But I also noticed it was configured for http on port 90.  I did that.  Years ago. Forgot about it.  For convenience when configuring NAT and such.  

I set that back to port 80.

Now I can see it with Firefox.  And log in.  And configure.

Perhaps it was all that port thing?

If so then that's an important part of this whole thing.  Any way of getting Firefox to discover what port configurations or to attempt different ones?

Perhaps some tool you know of I could have used?

So the answer to my question if I'm right in my surmises there would be "Because you've got a non standard http port configured on the device."

Thanks for your help.   :)

p.s. Sorry about the absence of carriage returns if you're seeing what I'm seeing. I've no idea what's causing that...

If you mean the different formatting of the first few lines, that is what happens when the line starts with a space.

I called for more help.