Thursday, May 28, 2015

Firefox Encountering "Secure Connection Failed" Error

I restarted Firefox (version 38.01) to visit a few secure sites, at present including, and encountered an error  as follows,

Secure Connection Failed

The connection to the server was reset while the page was loading.
  • The page you are trying to view cannot be shown because the authenticity of the received data could not be verified.
  • Please contact the website owners to inform them of this problem.

A screen shot is captured as follows,

This is actually a known problem, although it  took me a while to find out why it occurred and what a solution might be.

Apparently, the sites were still using older version TLS (i.e., TLS 1.0) that Firefox 37.0 or newer do not consider them as secure any more. See these two discussions.

To create a workaround for those web sites,  we will use Firefox's about:config page.
  1.  In Firefox address bar, enter about:config and hit the Enter key to open the about:config page.
  2. Search insecure_fallback_hosts and locate the setting for the attribute security.tls.insecure_fallback_hosts
  3. Double-click on the attribute to update its value. The value should be the host names of the sites you encountered the "Secure Connection Failed" error. The value can contain multiple host names, separated by a comma (","). For instance, if you encounter the error for sites and, the value would be,

This workaround works for me for a few sites. Be aware that Firefox has a discussion on addressing a similar problem; however, the solutions therein (e.g., rename or remove cert8.db) do not work for this particular error, i.e., the sites use older version of TLS (TLS 1.0).


  1. Thank you! This helped me track down a similar issue.

  2. I have just tried this solution and it does not work. Is there anything else I can do?

    1. Sometimes, you may have to restart Firefox.

      Be aware that Firefox pops up dialogue windows with exactly the same styles for many different types of security related problems. If it remains not working after you restart Firefox, was the error message exactly the same? If not, what was the error message?

  3. i have the 40.0.2 firefox version and i have this problem. I tested the proposed solutions and the problem continues. My problem is whit gmail. I test gmail in Chrome and Explorer and i can see my mails.

    1. Are you behind a firewall? Have you tried on a different network?

      I had similar problem when I was behind some corporate firewall. When I tried from a different network (e.g., went to a coffee shop), it was OK.

      I am sorry that I attempted to figure out what went wrong and has not gotten a solution yet (although, I am not sure if your problem exactly the same).

      So far based on the capture network messages, it was strange that the problem occurred when the client started sending data to the server (see the message diagram from F5) -- which meant the TLS/SSL handshake was completed. Definitely, Firefox handles TLS/SSL differently from other major browsers.

  4. Well written and very handy. It worked for me. Thank you so much.

  5. I have this problem and not only can't I open using FF I can't open using Chrome or IE either.

  6. Also having this issue, and ironically one of the websites it happens on is! So I can't even look at the links in your post.

    Your solution didn't seem to work for me, either.

  7. Thank you. Helped me!

  8. Hello.
    I have the same issue, except it's blocking me from all websites and browsers (including google) I have received the same error message and tried all sorts of methods to find the solution. It still doesn't work, and I don't know how to fix it.

    1. Hi,

      (1) Which version of Firefox are you using?
      (2) If you are using a laptop, try to access the websites from a different network, such as, a cafe, and see what happens. (Sometimes, Firewall settings in a network can be the source of the issue -- you may want to rule out whether the firewall has a role by doing this kind of test).