Proxy Response Error Codes: Frequently Asked Questions
IPDEEP
2026-02-03 15:24
Other
With the rapid development of the internet and the continuous expansion of various online businesses, proxy services have become an essential tool for protecting privacy, enabling secure access, and supporting data collection. However, during actual use, users often encounter various proxy response error codes. These errors not only affect user experience but may also pose business risks. Understanding the meaning of common error codes and their solutions is crucial for quickly troubleshooting issues and ensuring stable business operations.
Common Proxy Response Error Codes and Their Meanings
4xx Errors
① 400 Bad Request
A 400 error indicates that the request format is incorrect and the proxy server cannot understand the request. This is usually caused by abnormal request headers or incorrect parameters.
Solutions:
Check the request format and parameter settings.
Confirm whether required header information is missing in the proxy request.
② 401 Unauthorized
A 401 error occurs when the proxy server requires authentication but the user fails to provide valid credentials. This usually means the request headers lack correct authentication information.
Solutions:
Verify that the proxy username and password are correct.
Check whether authentication information is correctly configured in the proxy settings.
Ensure the authentication protocol used (such as Basic or Digest) matches the proxy requirements.
③ 403 Forbidden
A 403 error means the proxy server explicitly refuses the request. Possible reasons include IP bans, insufficient account permissions, or restricted access to the target website. This indicates the request was received but rejected due to security policies.
Solutions:
Check whether the proxy account has permission to access the target resource.
Replace the proxy IP to avoid using blocked IP ranges.
Contact the proxy service provider to confirm any usage restrictions.
④ 407 Proxy Authentication Required
This error is similar to 401 but specifically refers to proxy authentication failure. The request lacks valid proxy authentication headers.
Solutions:
Add correct proxy authentication information to the request.
Check proxy configuration to ensure all authentication parameters are complete and accurate.
5xx Errors
① 502 Bad Gateway
A 502 error indicates that the proxy server received an invalid response from the upstream server. This often results from connection issues between the proxy server and the target server.
Solutions:
Check the network status and health of the proxy server.
Wait for the target server to recover or switch to another proxy node.
Investigate firewall settings or possible network interruptions.
② 503 Service Unavailable
A 503 error means the proxy server is temporarily unable to handle requests, often due to overload or maintenance.
Solutions:
Wait for a while and try again later.
Choose a proxy node with lower load.
Confirm maintenance schedules with the proxy provider.
Others
① Timeout
A timeout error indicates that no response was received within the specified time limit. This may be caused by network latency, unresponsive proxy servers, or slow target servers.
Solutions:
Increase the request timeout setting.
Check local network conditions.
Switch to a proxy server with faster response speed.
② Connection Refused
This error occurs when the proxy server refuses to establish a connection, commonly due to incorrect proxy address or port, or firewall restrictions.
Solutions:
Verify the proxy server address and port.
Check firewall and network security settings.
Ensure the proxy server is running properly.
③ SSL/TLS Certificate Errors
When using HTTPS proxies, certificate verification failures may interrupt the connection. This often happens with self-signed or expired certificates.
Solutions:
Ensure the proxy supports HTTPS.
Trust the proxy certificate or disable certificate verification (testing environments only).
Use certificates issued by trusted Certificate Authorities (CAs).
How to Effectively Avoid Proxy Response Errors
1. Choose High-Quality Proxy Services
High-quality proxy providers usually offer more stable server resources, robust authentication mechanisms, and faster response speeds, significantly reducing error rates.
2. Rotate IP Pools Regularly
Using dynamic IPs or large IP pools helps lower the risk of bans and reduces frequent 403 or 401 errors.
3. Set Reasonable Timeout and Retry Mechanisms
Proper timeout thresholds and automatic retry mechanisms help handle temporary network fluctuations and proxy failures.
4. Ensure Accurate Authentication Information
Make sure proxy credentials and authentication methods are correct to avoid 407 errors.
5. Strengthen Log Monitoring and Alerts
Monitor proxy request status and error codes in real time to quickly detect and resolve issues.
Conclusion
Although proxy response error codes can be complex, most issues can be resolved by understanding their causes and applying targeted troubleshooting.
IPDeep provides high-quality proxy IPs, including:
With over 10 million high-quality IPs covering 200+ countries and regions worldwide, IPDeep helps your business achieve stable, fast, and secure network access.
