Firefox was blocking access to a test webserver I had setup on port 22 and giving me the error message "Access to port number given has been disabled for security reasons."
You can override any blocked ports by doing the following:
Type "about:config" into the address field and press Enter.
Right-click and choose New -> String.
Type or copy this string into the input field: network.security.ports.banned.override
Click OK
In the prompt for a value you type: 1080
or if you want to free multiple ports you can type in the numbers with a comma between them, or use a range like: 1080-1085.
Click OK
Source:
mozillazine post