Mozilla Firefox 413 error message on a Windows 10 PC

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Mozilla Firefox 413 error message on a Windows 10 PC


When using a bookmark previously used there is a 413 error message. on a Windows 10 PC, Mozilla Firefox goes into "not responding" mode after error message.


This is usually an issue with corrupted cookies that are send to the server as part of the HTTP request headers.


Clear the cookies from the website. To Inspect cookies and passwords and permissions for the domain in the currently selected tab follow these steps:-
    Click the Control Center 'i' icon at the left end of the location/address bar
  • Click the arrow to expand the Security Message
  • Click "More Information" and open "Tools -> Page Info"
  • Click "Security" to get Inspect and Modify Cookies and Passwords in a window
  • Clear the cookies

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 the file "cookies.sqlite" to "cookies.sqlite.old" and if present rename "cookies.sqlite-shm" and "cookies.sqlite-wal" (add .old to each) in the Firefox profile folder in case cookies.sqlite has 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.
  • Click Help
  • Click Troubleshooting Information
  • Click Profile Directory
  • Windows: Show Folder; Linux: Open Directory; Mac: Show in Finder

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