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bad request

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abarker

Bad Request

Your browser sent a request that this server could not understand. Size of a request header field exceeds server limit.

Cookie

Bad Request Your browser sent a request that this server could not understand. Size of a request header field exceeds server limit. Cookie

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Hi

This issue is usually caused by corrupted cookies.

Clear the Cache and remove the Cookies for websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences).

"Remove the Cookies" for websites that cause problems:

  • Options/Preferences -> Privacy & Security
    Cookies and Site Data: "Manage Data"

"Clear the Cache":

  • Options/Preferences -> Privacy & Security
    Cookies and Site Data -> Clear Data -> Cached Web Content: Clear

If clearing cookies didn't help then it is possible that the cookies.sqlite file in the Firefox profile folder that stores the cookies got corrupted.

  • rename/remove cookies.sqlite (cookies.sqlite.old) and when present delete cookies.sqlite-shm and cookies.sqlite-wal in the Firefox profile folder with Firefox closed in case cookies.sqlite got corrupted.

You can use the button on the "Help -> Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page.