A 404 response code can be caused by the user, an external website or your own website.
User:
- Manually enters an incorrect URL
External Website, Email or Ad:
- Links to your website with an incorrect URL
Your Website:
- The server is not properly configured to fulfill the requested action.
- The page has moved to a new location (new URL) without a redirect set in place
- The page is temporarily unavailable, perhaps because it is being worked on.
- The page has been permanently deleted with no redirect set in place
- An internal link is found on the website with an incorrect URL

