Ultimate Guide to Proxy Error Codes

Have you received an error code while using a proxy server? Pondering what it means and what to do next? You came to the right place! 

While proxy errors create hiccups in data-gathering operations, they are not too complicated to resolve.

In this article, you’ll learn about proxy error classification, the specific error codes, and how to solve them. So, let’s get straight to it.

Proxy Error Codes Explained

A proxy error is an HTTP response status code that tells you whether your web request to the target website through a proxy server was completed successfully.

Proxy error codes are grouped into five classes where each class indicates the nature of a response code:

• 1XX informational – the server received your request and is processing it
• 2XX success – your request was successfully processed and fulfilled
• 3XX redirection – the server accepted your request, but it requires further action to finalize
• 4XX client error – your request is incorrect or lacks required information, and it can’t be accepted by the target server
• 5XX server error – the server received your request but encountered an internal error while processing

Additionally, there may be other workarounds to specific errors, depending on the proxy provider. For instance, when using Oxylabs proxies, the 502 Bad Gateway can be solved by assigning a new IP address to the following requests. 

Thus, it’s always best to first refer to your proxy provider’s error codes and their solutions. With this in mind, we can now dive into the proxy codes.

1XX – Informational Responses 

100 Continue

The 100 response code states that you should continue the request if it hasn’t already been completed. You may receive this proxy status code when a request header has been received, but the server is still waiting for the request’s body.

101 Switching Protocols

This proxy code is a reply to the client’s request to change the communication protocol. It signifies the request has been accepted and specifies the new protocol to be used.

102 Processing (WebDAV)

If the target server needs more time to process the request, you’ll receive this proxy code. It indicates that the request has been received and is currently being processed.

103 Early Hints

Early hints tell the client what resources it can start preloading while the server is preparing a final response. This speeds up the browsing process, yet, being a fairly new addition to the HTTP status codes, you should note that not all web browsers support it.

2XX – Successful Responses 

200 OK

It means the request was successful, and the information, depending on the request method used, was delivered.

201 Created

The server fulfilled your request successfully, and new resources were created. You may receive this proxy code after making POST or PUT requests.

202 Accepted

This response code indicates that the server accepted your request, but the processing is still ongoing. Its goal is to allow the server to accept the request, which will be later handled by another process or server.

203 Non-Authoritative Information

You may receive this proxy status code when your request was successful, but the retrieved content was altered when compared to the content from the original server’s 200 OK response.

204 No Content

The 204 proxy code signifies a successful and fulfilled request, while there's no content to send back.

205 Reset Content

It indicates that the request was completed successfully and tells the user agent to reset the document view to its original condition.

206 Partial Content

You’ll receive this proxy code when using the Range header to retrieve only part of the requested resource.

3XX – Redirection Responses 

300 Multiple Choices

The multiple choices status tells that there are multiple responses, and the user agent or user should select the ones that it needs.

301 Moved Permanently

This proxy code is given when the target URL has been permanently replaced with another URL, which is provided in the response.

302 Found

It indicates that your requested resource is temporarily under another Uniform Resource Identifier (URI). As this can change later, the client should continue to use the original URI in future requests.

303 See Other

You may see this proxy code when the server redirects the user agent to retrieve the resource at a different URI.

304 Not Modified

The 304 status code is used for caching, and it tells the client it can continue using a cached response as it wasn’t modified and doesn’t differ from the original response.

305 Use Proxy

It signifies that a requested resource must be accessed via a specific proxy server. This proxy error code is not used anymore due to security reasons.

307 Temporary Redirect

This proxy code tells that the requested resource can be temporarily found under another URI and that the client must use the same HTTP request method as previously. 

For instance, if a GET request was used before, the following request must also use the GET method.

Solution: Make a request using the same HTTP request method to the provided URL.

308 Permanent Redirect

The 308 response code tells you that the requested resource has been permanently moved and can be accessed by using a new URI. Similarly to the 307 proxy code, the client must use the same request method as in the previous request.

Solution: Make a request to the provided URL using the same request method as before.

4XX – Client Errors 

400 Bad Request

This proxy code means the server can’t or won’t process the request due to a client error. The reasons can range from incorrect request syntax to deceptive routing.

Solution: Check your request for any syntax errors and make sure you’ve provided all the necessary details.

401 Unauthorized

The server will send this response when your request lacks valid authentication credentials to access the requested resource.

Solution: Provide the authentication credentials.

403 Forbidden

This proxy error code indicates that the target server received and understood your request but declines to provide access to the resource. 

If you get this error while using a proxy server, note that the target server might have blocked access due to certain suspicions.

Solution: You must employ various techniques to overcome this block. For example, you can rotate your proxies, use real user agents, and provide more HTTP headers to make your requests look as organic as possible.

404 Not Found

The 404 error tells you that the target resource can’t be found or the server is unwilling to confirm its existence.

405 Method Not Allowed

The HTTP request method you’ve used isn’t supported by the target resource. This response usually includes a list of supported methods so the client can re-do the request using an appropriate method.

Solution: Make another request using a supported method.

406 Not Acceptable

This proxy status code means that the target resource doesn’t have the content to send back as requested and specified by the user agent.

407 Proxy Authentication Required

Similar to the 401 Unauthorized status code, proxy error 407 points out that the client must provide authentication credentials to use a proxy server for this request.

408 Request Timeout

The timeout occurs when your request exceeds the time limit allocated by the server for the process to be completed.

Solution: Check your network connection and retry the request later.

410 Gone

You may receive this proxy error code when the content you’ve requested isn’t available anymore, which is likely to be permanent, and there’s no other URL the server can redirect your request to.

411 Length Required

The 411 proxy status code indicates that the server declined your request due to a missing Content-Length header, which is required.

412 Precondition Failed

It means the server can’t fulfill your request due to the server’s inability to meet certain preconditions defined in the request header fields.

 413 Content Too Large

The 413 proxy code signifies that the request's content is too large for the server to process.

415 Unsupported Media Type

The server provides this response when it refuses to process the request because the content format isn’t supported by the target resource. Usually, this error involves Content-Type and Content-Encoding headers.

422 Unprocessable Content

You may get this proxy code when the server can’t process the request due to its semantic errors, even though it is syntactically correct.

423 Locked

The target resource you’re trying to access is locked.

424 Failed Dependency

If you make subsequent requests, you may get this response code when your request fails because the previous request also failed.

426 Upgrade Required

The 426 proxy error code signifies that the server refuses to process your request using the specified connection protocol but might do so after you change to a supported protocol, which is provided in the response.

429 Too Many Requests

You’ll receive this error message if you have made too many requests in a certain timeframe.

Solution: Utilize proxy rotation for each request so the target server would see many requests from different IP addresses.

431 Request Header Fields Too Large

This proxy code means the server has refused to process your request as it contains header fields that are too large or too long.

5XX – Server Errors

500 Internal Server Error

Proxy error 500 indicates that the server ran into an unexpected situation that obstructed its process to execute the request.

Solution: Retry the request at a later time.

501 Not Implemented

You may receive this proxy error when the server doesn’t recognize and doesn’t support the HTTP request method used.

Solution: Make another request using a supported method.

502 Bad Gateway

The 502 proxy code tells that the target server received an invalid response while working as a gateway to retrieve a response from an upstream server.

Solution: Retry the request. If it doesn’t work, make a request to another website to make sure this error is specific to this server. 

If you’re using a browser, an effective next step could be to clear the cache and cookies. Additionally, you can try changing your DNS.

503 Service Unavailable

It means that the server can’t process your request at this time. There are various reasons behind this response, but in most cases, it can indicate that the server is overloaded or is on scheduled maintenance.

504 Gateway Timeout

Similarly to the 502 Bad Gateway error message, the server may send this error when it doesn’t retrieve a response from an upstream server in time.

511 Network Authentication Required

This status message means that the client must authenticate to gain network access. 

Solution: Provide the network authentication credentials and ensure they’re correct.

Wrapping Up

As you can see by now, proxy error codes aren’t too difficult to crack. However, it might be burdensome to solve them. Remember that it’s always best to take your time to analyze the invalid request which initiated the error. 

Rest assured that with the knowledge provided in this article, you now know more about what is a proxy error.