Proxy server error values and how to fix them

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Proxy server errors can arise for various reasons, each with its specific nature. Addressing these issues requires a thorough analysis of error messages, checking proxy server settings, event logs, and, if necessary, contacting the proxy provider's support. The most common proxy errors include:

  • 407 - Proxy Authentication Required
  • 400 - Bad Request
  • 403 - Forbidden
  • 404 - Not Found
  • 429 - Too Many Requests
  • 500 - Internal Server Error
  • 502 - Bad Gateway

This article will detail each error and how to correct the proxy error.

What is a proxy server error?

A proxy sever error is an error message indicating problems in the operation of the proxy server used to process network traffic between the user's device and the remote server that cannot be accessed.

Errors can occur due to:

  • Connection problems;
  • Incorrect configuration;
  • Authentication issues;
  • Network problems;
  • Access restrictions;
  • Software issues.

The solution to proxy server errors depends on the specific reason for their occurrence.

Overview of main proxy server errors

Let's take a closer look at the main proxy server errors, their causes, and solutions.

407 - Proxy Authentication Required


The "407 - Proxy Authentication Required" error indicates that access authentication for the proxy server is required. It occurs when a user has not entered or incorrectly specified the login and password for a private proxy, or if authorization was set to a static IP during purchase but the user's home IP has changed. To fix this error, ensure that the proxy server authentication data is entered correctly. It's also recommended to check for software updates or configure the proxy in another browser, as this problem may be specific to a particular program.

Correcting this error typically involves verifying the accuracy of the proxy authentication details. Users should double-check the username and password, or, if using IP authentication, ensure their IP address matches the one registered with the proxy provider. Updating the software or attempting to configure the proxy settings in a different browser can also help resolve this issue, as it might be related to software compatibility or specific settings within a particular application.

400 - Bad Request


The "400 - Bad Request" error indicates that the server cannot process the request from the browser due to:

  • Incorrect HTTP request syntax or missing required parameters in the request, such as an improperly specified link.
  • Software or viruses on the PC that block the site's operation.
  • Outdated cookies files.

Solutions for this problem include clearing the cache and cookies, disabling or adjusting internet connection settings in the antivirus, and installing new versions of network adapter drivers.

403 - Forbidden


The "403 Forbidden" error indicates that the server recognizes the request but refuses to execute it due to access restrictions. Reasons for this error can include a lack of access rights, incorrect credentials, restrictions, or location-based blocking, where the server may limit access from certain IP addresses or block access from certain countries. To resolve this error, you should:

  • Contact the administrator of the end server for more information.
  • Ensure that the IP address's location is not blocked by the resource being accessed.
  • Configure the firewall to ensure it does not block access to the resource.

404 - Not Found


The "404 Not Found" error indicates that the server cannot find the requested resource. This means the user has made a request for a URL that does not exist on the server. Typically, this error is displayed if the client requests a page or resource with an incorrect or outdated URL, the resource was deleted or moved on the server, or the user does not have access rights to the requested resource. Possible solutions for the 404 Not Found error:

  • Verify the URL you are accessing to ensure it is correct and matches the server's structure.
  • If the resource has been moved or deleted, try contacting the server's administration for more information.

429 - Too Many Requests


The "429 Too Many Requests" error signifies that a user has sent too many requests in a given timeframe, exceeding the server's established limits, leading the server to reject any additional requests. This measure prevents server overload and maintains stable performance. To resolve this issue, try the following actions:

  • Reduce the rate and number of requests sent to the server. Adhere to the server's set limitations.
  • Implement longer delays between sending requests.
  • If the server returns a “Retry-After” header, it indicates how long the client should wait before retrying the request without the risk of receiving a 429 error again. Follow the guidance in this header.
  • If repeated requests to a specific page on the server are necessary, consider implementing caching to reduce the frequency of subsequent requests.

500 - Internal Server Error


The "500 Internal Server Error" is a generic response for various problems on the server, indicating that the server encountered an unexpected condition that prevented it from fulfilling the user's request. Causes can include software issues, database problems, configuration errors, insufficient server resources, server problems, and errors in the .htaccess file (for servers using Apache). To address the "500" error, try the following actions:

  • Try accessing the resource again after some time.
  • If you cannot identify the cause of the error, contact the server administrator or hosting provider for assistance.

502 - Bad Gateway


The "502 Bad Gateway" error is a proxy server response indicating that the proxy failed to receive a valid response from the upstream server. This error occurs when the proxy server cannot establish communication with the server, receive a response, or forward the response to the user. Common causes include incorrect proxy server settings, network configuration problems, and the inaccessibility or downtime of the upstream server. To resolve this error, consider the following actions:

  • Check the availability of the upstream server.
  • Verify network settings and connection integrity.
  • Try restarting the proxy server. This can help resolve temporary issues in its operation.
  • Ensure that the proxy server settings are correct, including the IP address, port, and other parameters.
  • Temporarily disable the proxy server and try to access the resource directly. If the error does not occur, the problem may be related to the proxy server, in which case, contact the proxy provider's support for assistance.

Recommendations for fixing proxy server errors

The most relevant methods for solving problems caused by proxy errors include:

  • Checking the proxy server settings, which entails verifying the accuracy of the IP address, port, authentication data (if using private proxies), access rules, and other parameters.
  • Clearing the browser's cache and cookies, as temporary files and data stored in the browser cache can cause conflicts related to the site or proxy server.
  • Reinstalling the web browser can resolve configuration conflicts and eliminate potential damage in the software files.

Note that these recommendations are general, and specific steps may vary depending on the proxy server and browser used. Also, before making changes to settings or reinstalling the browser, it's advisable to create backups of important data to avoid loss of information.