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Why does the new Firefox return an unreliable source error even for mozilla.com on this WIN8.1 computer?

  • 4 replies
  • 28 have this problem
  • 2064 views
  • Last reply by cor-el

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I updated to the new Firefox. When I try to load a page, I get an "untrusted" source error, even for sites such as support.mozilla.com (any mozilla.com site I have tried) and other sites that I have previously used regularly. The message actually says, "This connection is untrusted." Right now, even google search is untrusted. I can click "I understand the risks" and get an ominous warning. I can also get the "Uh-oh, something went wrong! Error Code 404" when I try one of my standard web sites, including my normal home page. Interestingly, the bottom of the screen informs me that Firefox is automatically sending data to improve my experience.

When I tried to download the new Firefox again, It went to all but the last .1 (3 seconds remaining) and stalled several times.

I have Windows 8.1 and am posting this on a different browser.

All Replies (4)

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hello, first please make sure that the date & time is set correctly on your system. if this doesn't solve the issue (or it is already set properly), a possible solution depends on different factors:

  • what is the error code shown under technical details on the error page?

in case the error code equals sec_error_unknown_issuer, please attempt to add an exception on the bottom of the error page & inspect the certificate (see the screenshot attached for instructions):

  • which issuer information does the certificate contain?

thank you!

"This Connection is Untrusted" error message appears - What to do

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Also check the date and time in the clock on your computer: (double) click the clock icon on the Windows Taskbar.

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I think something else is going on here, though I am very open to being wrong. Does Firefox really have a message that says "Uh-oh, something went wrong! Error Code: 403"? This message is showing up both in IE and Firefox. I know it's not IE's. I recently downloaded Firefox and don't think that it started showing up in IE at this time. I have also had to deal with a PUP taking over IE on my work computer. Some buying site (not Amazon's) with green in logo, but can't remember what. I did use it's own instructions to remove, but wonder if it is really removed. I have had more fishing takeovers on IE lately. When I look up the message on Google, it seems to be popping up in other programs and websites. Could we have a new virus here? I learned a long time ago the strange messages of the type Uh-oh were likely indications of a virus. So again the question, does Firefox really use Uh-oh in it's standard 404 message?

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Such 40x messages are usually send by the server as an HTML page in case of an error.


Do a malware check with several malware scanning programs on the Windows computer. Please scan with all programs because each program detects different malware. All these programs have free versions.

Make sure that you update each program to get the latest version of their databases before doing a scan.

You can also do a check for a rootkit infection with TDSSKiller.

See also: