What are error codes?
The error codes is the way in which server tells people about the encountered error. There are many error codes, some of the most common error codes are 401 (Unauthorized), 403 (Forbidden), 404 (Not Found) and 500 (Internal Server Error).
You can also set up custom error pages for these error codes. With custom error pages, your website visitors will see the error messages you set instead of default error messages.