Beginning yesterday, Firefox started returning this error:

for lots of sites, including LinuxQuestions.org and duckduckgo.

But I am accepting cookies from all. I've cleared the cache (by deleting the files with an rm -rf as well as CtlShiftDel in Firefox) and the cookies.sqlite file. I've also allowed tracking. I've done everything suggested at Mozilla's support site. Firefox 28.0. Latest Slackware, kernel 3.14.1 (build it myself).

I'm doing this in Opera.

Maybe the problem is somewhere in the Firefox configuration files. Rename your .mozilla directory (for example call it .mozilla.old) and then start Firefox again and see if the problem persists.
jdk

Firefox has returned to working today as it did 3 days ago. I guess sleeping on it - I did nothing else - 'fixed' the problem.

There are things that Man was never meant to understand (cue eerie music).
jdk

1 members found this post helpful.

The URI in the address bar was from opendns, not the target domain; it may have been a defect in their records, perhaps something funny in its cache.

Yes, that usually happens when their (the target domain's) server is down.
jdk

I recently upgraded to firefox 34 from 17. I never received this message be fore. Gmail worked for awhile now I get the message continuously. What gives? I tried the on line help that says go to Tools > Options > Advanced > Network > Cached Web Content: "Clear Now",
Another says Tools/Options/Privacy - Click "Remove Individual Cookies"
Problem is that 34 does not have a "Options" in the "tools" menu. At least not in the 34
that I have. Where is the some thing in 34? Or has someone come up with a better fix?

Some how this got posted in another thread. I did find out that "Preferences" is the new
"Options" So I go to cookies and delete them. This works for a while. It comes back after
a while. The thread said this is "solved" I did not seer a solution other then keep going back into cookies and deleting. To me this is not a good solution. What is the permanent fix?

This stuff is in tools/options in Firefox for Windows, edit/preferences in Linux. I think it's always been that way.

Cookies? not cache? Does it happen for every site or just Gmail?

There was no solution. I marked it as solved to keep LQers from trying to help. 'Killed' would have been better but isn't a choice

I only use Puppy 5.6. And the Firefox 34 for linux. And it uses Edit/preferences to get into "History" then cookies. final is "Remove All Cookies" Tried to just delete gmail cookies.
That did not work. There must be another site that is leaving a cookie that messes up gmail???
Or there is a "*" icon on the tool bar that goes right to "History"
I used 17 before and had no problem. People with 28 and 31 had the same problem with gmail other sites .

Only gmail so far.

Is this not a help site? Why would you kill a thread that is trying to help others with a problem?. I am offering help in my post. Not a complete solution but at least I can now use gmail for a while. If I do find a solution I will post on this thread. If someone can find
the cookie that is causing the problem please post it so we all know. Or maybe there is another
solution.

I have usually gotten excellent support from Mozilla's site.