Check server headers and verify HTTP status codes. There are seven HTTP status codes that we are primarily interested in from an indexing and search engine marketing perspective. It is recommended that you verify your URIs are returning the proper Status-Code in the Server Header.

Status Code Description
200 OK The request has succeeded. The information returned with the response is dependent on the method used in the request.
301 Moved Permanently The requested resource has been assigned a new permanent URI and any future references to this resource SHOULD use one of the returned URIs.
302 Found The requested resource resides temporarily under a different URI. Since the redirection might be altered on occasion, the client SHOULD continue to use the Request-URI for future requests.
304 Not Modified If the client has performed a conditional GET request and access is allowed, but the document has not been modified, the server SHOULD respond with this status code. The 304 response MUST NOT contain a message-body, and thus is always terminated by the first empty line after the header fields.
307 Temporary Redirect The requested resource resides temporarily under a different URI. Since the redirection MAY be altered on occasion, the client SHOULD continue to use the Request-URI for future requests. This response is only cacheable if indicated by a Cache-Control or Expires header field.
404 Not Found The server has not found anything matching the Request-URI. No indication is given of whether the condition is temporary or permanent.
410 Gone The requested resource is no longer available at the server and no forwarding address is known. This condition is expected to be considered permanent.