I like Firefox. A lot. Even when it was named Phoenix.
I even use it at work (using PortableApps.com).
But some sites (ok, only StackExchange sites) I visit I get multiple popups asking for my user name and password. Because I’m behind a firewall I have to enter my credentials, no big deal. But they don’t work! So I have to hit Cancel. Not just once, but, like, 4 times!
Annoying Popup
Annoying Popup 2
And it’s not the HTTP proxy, it’s asking for a “moz-proxy”.
I finally decided to Google my issue. I found some reports of others with the same issue. (Ironically, the last page was from a StackExchange site and produced the error.)
When I found a page suggesting it was a Firebug issue I opened it and found a bunch of “407 Proxy Authentication Required” errors for http://sockets.ny.stockexchange.com.
I also found these errors in the Javascript Console.
When I saw the “ws” protocol I was pretty sure the issue was with web sockets.
I decided to look to see if I could turn this off.
Google didn’t provide any obvious hits, but at the bottom of this page it mentioned turning on web sockets. So I looked in “about:config” and filtered on “socket”.
Sure enough, I was able to disable web sockets! Hurray! And now I don’t get those popups! Problem solved!
(This bug seems to be related.)
(Maybe I can make this guy hate Firefox a little less.)
More discussion and a possible solution.
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Nice, thanks for this — works for me too (and I have Firebug installed…)
Thanks – this issue with Firefox had been driving me nuts. You’ve made my day!
Thanks, this is the only solution I have found so far.
https://trello.com/ was causing this to pop up all the time.
I didn’t even know there was an error console!
But it clearly gives me the cause of the problem
Error: Firefox can’t establish a connection to the server at wss://trello.com/socket.io/1/websocket/…
Thanks worked for me as well! Good trick!
It was very annoying
thanks for the help!
All is good for me too after change this value to “false”
Awesome. Thank you.
I dont have Firebug installed and was having this issue with an Enjin site. fixed it right up. 
Thanks for the Info it works like charm
Thanks to your blog entry I finally got rid of that annoying dialog.
This didn’t work for me, at least in the firebug console I keep getting the anoying error.
Take this as a +1 (as g+ is blocked over here). Saves me a lot of clicking.
I wasn’t having an issue with the dialog, only the persistent errors in firebug. Needless to say that the method did not work for me. Thanks anyway, I might be able to help someone with the same issue later on.