HTTP Network requests return StatusCode (status code) 200, 300, 400, 500 .... _ Network

201-206 indicates that the server successfully processed the requested status code, indicating that the Web page can be accessed normally.
200 (successful) the server has successfully processed the request. Typically, this indicates that the server has provided the requested Web page.
201 (created) The request was successful and the server has created a new resource.
202 (accepted) the server has accepted the request but has not yet processed it.
203 (non-authoritative information) the server successfully processed the request, but returned information that might be from another source.
204 (no content) the server successfully processed the request but did not return any content.
205 (reset content) the server successfully processed the request but did not return any content. Unlike the 204 response, this response requires the requester to reset the document view (for example, to clear the contents of the form to enter new content).
206 (partial content) the server successfully processed a partial GET request.

300-3007 means: To complete the request, you need to do something further. Typically, these status codes are always redirected.

300 (multiple selections) the server can perform multiple operations on request. The server can select an action based on the requester or provide a list of actions to choose from.

301 (permanently moved) The requested page has been permanently moved to the new location. When the server returns this response, the requestor is automatically transferred to the new location. You should use this code to notify search engine spiders that Web pages or sites have been permanently moved to a new location.
302 (Temporary move) The server is currently responding to requests from Web pages in different locations, but the requester should continue to use the original location for subsequent requests. Automatically moves the requester to a different location. However, since search engines will continue to crawl and index existing locations, you should not use this code to tell search engines that pages or Web sites have been moved.
303 (View other locations) The server returns this code when the requester should make a separate GET request to retrieve the response in a different location. For all requests except the head request, the server automatically transfers to a different location.
304 (not modified) The requested page has not been modified since the last request. When the server returns this response, the content of the Web page is not returned.

You should configure the server to return this response if the Web page has not changed since it was last requested by the requestor. Because the server can tell the search engine since the last crawl after the Web page has not changed, so it can save bandwidth and overhead.

305 (using a proxy) the requester can only use the proxy to access the requested Web page. If the server returns this response, the server also indicates the agent that the requester should use.
307 (temporary redirection) The server is currently responding to requests from Web pages in different locations, but the requester should continue to use the original location for subsequent requests. Automatically moves the requester to a different location. But since search engines continue to crawl and index existing locations, you should not use this code to tell a search engine that a page or site has been moved.

A 4XXHTTP status code indicates a possible error in the request and can impede server processing.

400 (Error request) The server does not understand the syntax of the request.

401 (authentication error) this page requires authorization. You may not want to include this page in the index.

403 (Prohibited) the server refused the request.

404 (Not found) the server could not find the requested Web page. For example, this code is often returned for pages that do not exist on the server.

For example: HTTP://WWW.0631ABC.COM/20100AAAA, you will go to the 404 error page

405 (method Disabled) Disables the method specified in the request.

406 (not accepted) cannot use the requested content attribute to respond to the requested Web page.

407 (proxy authorization required) This status code is similar to 401, but the specified requester must authorize the use of the agent. If the server returns this response, it also indicates that the requester should use the proxy.

408 (Request timed out) timeout occurs when the server waits for a request.

409 (conflicting) the server encountered a conflict while completing the request. The server must contain information about the conflict in the response. This code may be returned by the server in response to a put request that conflicts with the previous request, as well as a two-request difference list.

410 (Deleted) The server returns this response after the requested resource has been permanently deleted. The code is similar to the 404 (not Found) code, but is sometimes substituted for 404 code in cases where the resource existed before and is not present. If the resource has been permanently deleted, you should use 301 to specify a new location for the resource.

411 (requires a valid length) the server does not accept requests that do not contain a valid content Length header field.

412 (Prerequisites not met) the server did not meet one of the prerequisites that the requester set in the request.

413 (Request entity too Large) the server was unable to process the request because the request entity was too large to handle the server.

414 (The requested URI is too long) The requested URI (usually the URL) is too long for the server to process.

415 (Unsupported media type) The requested format is not supported by the requested page.

416 (Request range does not meet the requirements) if the page cannot provide the requested range, the server returns this status code.

417 (expectations not met) the server did not meet the requirements for the "expected" Request header field.

500 to 505 means that the server encountered an internal error while trying to process the request. These errors may be errors on the server itself, not the request.

500 (server internal error) the server encountered an error and could not complete the request.

501 (not yet implemented) the server does not have the capability to complete the request. For example, the server might return this code when the request method is not recognized by the server.

502 (Error Gateway) the server, as a gateway or proxy, received an invalid response from the upstream server.

503 (Service Unavailable) the server is not currently available (due to overloading or downtime maintenance). Usually, this is only a temporary state.

504 (Gateway Timeout) the server, as a gateway or proxy, did not receive requests from the upstream server in a timely manner.

505 (HTTP version is not supported) the server does not support the HTTP protocol version used in the request.