Fixing SEC_ERROR_INADEQUATE_KEY_USAGE in Firefox
This post explains how to fix the SEC_ERROR_INADEQUATE_KEY_USAGE error that sometimes occurs when you visit a secure url in Firefox.
When loading a secure url (https) in Firefox, you see "Secure Connection Failed", "Error code: SEC_ERROR_INADEQUATE_KEY_USAGE".
- Go to
about:profilesin Firefox. Do this by entering "about:profiles" in the address bar like a URL.
- Locate the profile that is currently in use. This will be the profile that has no Remove button.
- Click Open Folder in Root Directory.
- Delete the cert9.db and cert_override.txt files. You may need to close Firefox to delete these files.
- Try problematic url again. The problem should be resolved.