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

Configure firewalls so that Firefox can access the Internet. {web link}

My older version of firefox v49 work fine on the same platform. Any way to solve this with about:config Or if any other. THANKS

My browser can access the internet as well.firewall installed and on. But some time server jam or internet slow connect case page failed and firefox turn request POST to GET. But firefox 49 or older work fine on same pc same os. I try this some of friends pcs. But all the time I face the same problem. THANKS

I called for more help.

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

Start your Computer in safe mode with networking. Then start Firefox. Try Safe websites. Is the problem still there?

Starting The Computer In Safe Mode;
Free Online Encyclopedia

I don't see this kind of failure often enough to have experienced a change myself.

What I recall is: when you reload after a failed POST, Firefox would display a warning that the data would be resubmitted (presumably to protect you against a situation like a double-payment).

Q1: Does Firefox 50 give you that warning in this situation?

Q2: How are you reloading, for example, Ctrl+r, clicking the arrow in the toolbar, etc.?

My concern would be that you need to reload in a way that does not bypass the cache because the page is posting to itself, and therefore a reload bypassing the cache may well simply re-request the original page. Not sure why that would be different between Firefox 49 and 50.

Q3: Are you using the site in a regular window or a private window?

It's odd that you have a login page on http instead of https. Could that be a factor, Firefox no longer wanting to send username/password on http?

I want to resend popup dialog box its not come when my connection failed for other reason of page load failed. The latest version of firefox not show on failed page Try Again to load that page.

• I just click on "Try Again"

Firefox v49 or older give me popup dialog box for "resend" data. but latest not giving me that. I tried 4 - 5 pcs. I entry some dada on website and i really need this "resend" popup, otherwise my form fillup work going waste of time, there are a lot of fields to fillup. I uninstall latest version of firefox and use firefox V49. So please HELP me I really want to use latest version of firefox.

We need a testcase to reproduce the issue on our side and find a possible regression in FF50. Could you share your website URL or build a testcase (on jsfiddle or codepen)?

Just for testing fill up any POST method form and disconnect internet and submit the form. Now you get page load error message and "Try Again" button. Internet connect again and click on "Try Again". See there are no popup for "resend" on firefox v50 but I want the popup. If you try this firefox v49.0.1 you get the "resend" popup.

test here, go, disconnect your internet connection(for testing) and click submit https://goo.gl/d5WTVY then click Try Again.

Same problem in this demo posting to a different page:

https://www.jeffersonscher.com/res/posttest.html

The "Try Again" button calls this code:

// Session history has the URL of the page that failed
// to load, not the one of the error page. So, just call
// reload(), which will also repost POST data correctly.
try {
  location.reload();
} catch (e) {
  // We probably tried to reload a URI that caused an exception to
  // occur;  e.g. a nonexistent file.
}

Not sure what changed here. Judging from the old text in the source, it was unintentional.

Yes I know.

The resend popup come when page loaded. But if page loaded failed(like The site could be temporarily unavailable or too busy) the resend popup not show.

Ok, Please follow bellow steps: 1. Go https://www.jeffersonscher.com/res/posttest.html 2. Disconnect your internet connection.(for get Unable to connect) 3. Submit and wait for "Problem loading page" 4. Reload or "Try Again" or window,reload() do what ever you want. 5. this time not showing me the resend popup.

I hope you understand the exact problem this time which I can not explain.

Do you want to file a bug? https://bugzilla.mozilla.org/enter_bug.cgi

You can include a link to this thread in case they want additional background.