It seems as a security touch to Firefox it is now blocking non standard HTTP ports. Kinda of annoying really. To override this type this in the address bar
about:config and search for
network.security.ports.banned.override. This may or may not exist, if it doesn’t, right click anywhere in the window and select new->string and use
network.security.ports.banned.override as the name and the port number you need to connect to as the value. You can also select a range of ports by using
1-1024 as such a value or as a CSV style values such as
1024, 8080, 1-1000, 80… et cetera.