Note to self - Firefox and local connections

 Whilst trying to hit my NAS from Firefox on my Mac, I kept seeing errors such as:-

Unable to connect

Firefox can’t establish a connection to the server at 192.168.1.23:5000.

    The site could be temporarily unavailable or too busy. Try again in a few moments.
    If you are unable to load any pages, check your computer’s network connection.
    If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the web.
    If you are trying to load a local network page, please check that Firefox has been granted Local Network permissions in the macOS Privacy & Security settings.

The same page worked in Safari, and I was able to SSH into the NAS, so knew that the network was not a notwork :-)

There's a clue in the last sentence of the error, which is nice ( and, I suspect, may have been added recently ) : -

If you are trying to load a local network page, please check that Firefox has been granted Local Network permissions in the macOS Privacy & Security settings.

Yes, you've guessed it...

Once I checked the box for Firefox, I was off to the races ...