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Most Common Proxy Errors

Various web scraping or crawling jobs can quickly stop when you receive a proxy error. These response codes can interrupt the most important tasks and become a real pain. However, knowing what those three-digit codes mean can help you quickly resume the tasks. 


Proxy errors can come up for a number of reasons. Some of them, such as internet connection issues, can be easily fixed. Meanwhile, others may require further investigation and more effort. In some cases, their solutions can be completely out of your hands, for example, if you receive a web server error that has nothing to do with your request. 


However, familiarizing yourself with the proxy error codes will help you fix them quickly and with less effort. We listed all the most common proxy error codes with explanations. We also provide suggestions of how to solve each error, so you can come back to this page whenever you run into an issue.

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What is a Proxy Error?


Proxy error is an HTTP error status that may appear as a response to your request sent to a web server. This error indicates that your proxy has failed. Regardless of the cause, you’ll have to find a solution if you want to continue using the same proxy. 


There’s an entire list of proxy error codes that may appear as a response to your request. These codes may indicate the issue, and understanding them can help you resolve it. You'll quickly figure out the proxy errors if you're familiar with HTTP status codes.


Why am I Getting a Proxy Error?


You can get a proxy error for a number of reasons. The error may come from your side or be caused by the proxy server. The most common reasons for getting a proxy error are: 

  • You got a ban from a web server
  • Your proxy settings are wrong
  • You can’t connect to proxy server


Understanding the proxy error codes can help you solve the issue and let you continue carrying out your tasks.


A List of Proxy Error Codes


To understand the codes, you should remember some general information. Proxy error codes contain three digits, and the first digit always indicates the response group. There are five main response groups, and each code from that group sends a different error message. 


You may also receive a 0 HTTP error code. This status code means you’ve got a connection error, and you won’t receive any response from the server. To solve this error, check your internet connection and make sure you entered the domain name correctly. Connection errors may also be caused by a third-party security tool or an anti-virus system. One more reason may be a proxy connection timeout, so you can try refreshing your request.


Information Response


1XX error codes send an informational message, but they rarely come up in practice. These codes don’t indicate any real errors, but inform you about the status of your requests.


100 — Continue 


This code means that part of your request has been received by the web server and you can start sending the rest of the request.


102 — Processing


You may receive this code if you send multiple sub-requests with complex requirements. It means that the server received your requests and is taking time to process them.


Success Response


All HTTP response codes starting with 2 indicate that your request has been sent to the target, and you received a response. Although 2XX codes indicate success, you should be wary of all the 2XX codes that aren’t 200 because they may refer to an error.


200 — OK


The best code you can expect. It means your request has been successful. However, the definition of success depends on your HTTP method (GET, HEAD, POST, etc.)


201 — Created


The server has fulfilled the request and created a new resource based on the request. 


202 — Accepted


The request has been received, but it hasn’t yet been processed. The actual response will be known once the request is processed.


203 — Non-Authoritative Information


Returned data is not exactly the same as that provided by the original server. The data has been collected from local or third-party content. 


204 — No Content


The request has been successful, but there’s no content to return. 


205 — Reset Content


If you receive this code, you should reset the document that sent this request. The code indicates that there’s no content to return, but you should take action here.


206 — Partial Content


The server has returned part of the content. This may appear if you set a range in the request header.


Redirection Message


3XX error messages mean that you’ll need to take action. These errors are less likely to occur if you’re using a web browser because browsers don’t tend to follow more than five consecutive redirections triggered by the same request. However, if you're using your own script, you may get trapped in an infinite loop of redirections.


300 — Multiple Choices


If your requested URL is leading to multiple resources, this error status will pop up. To fix this issue, make sure your URL is leading to a single resource.


301 — Moved Permanently


301 is the most common redirection message. It means that the target has been permanently moved, and the crawler or a scraper is redirected to a different URL. This error code doesn’t require any action unless the URL is redirected to multiple pages. In that case, it can create an infinite loop.


301 — Resource Moved Temporarily


The URL you’re accessing has been temporarily moved, and you’re redirected to a different URL. 


304 — Resource Modified


The target has not been modified since the last time it was requested. You can continue with the same cached version.


Client Error Response


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All the 4XX error messages indicate that there’s an error from your side. The issue can be related to the browser, automation bot, or the request itself. Sometimes you can fix this error by adjusting your proxy settings.


400 — Bad Request


This is a generic response that tells you there’s something wrong with your request. The most common reasons are that your proxy server or the target site cannot parse your request. 


401 — Unauthorized 


This error is returned by proxy servers once the web servers require authentication. If you receive this code, you need to provide your credentials and authenticate yourself.


403 — Forbidden


Your request is valid, but the target’s server refuses to respond to it. This may happen if you don’t have permission to access the target.


404 — Not Found


Your request is valid, but your requested resource isn’t available. The target URL may be incorrect, changed without redirection, or removed from the requested site.


407 — Proxy Authentication Required


A proxy may require authentication for a number of reasons. Such as: inaccurate credentials, wrong authentication with the proxy provider, or you haven’t whitelisted your IPs. 


To solve this error, update the proxy settings with whitelisted IP addresses and re-enter your credentials.


429 — Too Many Requests


Sending too many requests in a short time can lead to receiving this error code. This may also show up if you send too many requests using the same IP. Websites have restrictions to protect themselves from attackers or avoid overloads, and this error is the result of triggering their security systems. 


To avoid this error, use rotating proxies and set delays between requests.


Server Error Message


5XX error messages indicate that the server has successfully received your request but cannot process it. Server errors can be solved by adjusting your proxies. For example, rotating proxies, changing the network, or the IP type. 


500 — Internal Server Error


This error comes up when the server runs into an unexpected condition that holds it from responding to the request. Contact the server owner and let them know about the issue.


502 — Bad Gateway


The server that works as a gateway to receive a response needed for the request handling got an invalid response. This error may suggest that your requests have been indicated as sent by bots.


To solve this issue, clear your cache and cookies. If that doesn’t help, change the DNS and try using your browser without proxies and with default settings.


503 — Service Unavailable


Check the status of the requested server because it may be down for maintenance or overloaded. It may also indicate that your proxy received a CAPTCHA it’s not able to solve. Try using rotating IPs.


504 — Gateway Timeout


This error comes up if your proxy server doesn’t receive a timely response from your target website. The server may still be processing the request, but the proxy server has timed out. 


To solve this error, adjust your timeout header settings or get in touch with the proxy provider to find out if it’s a proxy server error.


Solve Proxy Errors with Residential Proxies


If you’re using datacenter IPs and constantly receive errors that are related to the proxy servers, consider using residential proxies. These proxies act like regular internet users and are less likely to get banned or cause an error.


Residential proxies are more expensive than datacenter IPs, but they’re much less likely to get identified as proxies by the target website. These IPs come from Internet Service Providers (ISPs) and are connected to residential locations. 


Rotating proxies can be an easy solution to a number of proxy errors. For example, 429 and 503 HTTP error codes can be fixed by rotating your proxies at set intervals. 


Metrow Residential Proxies have high uptime, which means you are less likely to receive proxy errors due to the proxy server issue. These IPs also benefit users with high performance. Residential proxies can help perform various scraping or data gathering jobs with fewer errors.




Proxy errors are a common issue, and understanding them can help you save time and resources or even avoid the errors altogether. The more web scraping or crawling jobs you do, the more errors you’ll run into, so familiarizing yourself with their meaning can be very helpful.


Proxy errors, or HTTP errors, come in five main response groups. Each group suggests what kind of issue you’ve run into and can indicate what action is required from your side.

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Errors that begin with 1 send an informational message and don’t suggest any real issues with your proxy connection. 2XX messages mean a successful response and rarely require any specific actions. 3XX indicate redirections and may suggest checking your settings as they may lead to a proxy server error.


Meanwhile, 4XX and 5XX proxy error codes indicate issues with your request or your proxy server connections. These errors require action and may stop your data gathering jobs.


You can avoid most errors by using residential proxies. These IPs resemble organic internet users, so web servers are less likely to send an error message to them. 


By Oliver Jones
Oliver is someone you would call a tech-wizard. Fascinated with everything computer and machine related, he has been involved in the industry for ages. Proxies and data are his two newest interests that have carried him to the field of writing. Oliver believes that all the knowledge in the world is worth nothing if it can’t be shared!