Proxy Issue Solving in Data Fetching Automation

We are looking for an experienced backend developer or network specialist to resolve a "403 Forbidden" network error in our current data fetching automation that only occurs when traffic is routed through a proxy.

Without a proxy, the system works perfectly and completes requests successfully. The issue appears to be a technical configuration mismatch that arises when the proxy layer is added.

Current Situation:
- The system successfully retrieves data via direct connection (without proxy).
- When configured with a proxy, requests are rejected with a 403 Forbidden error.
- Standard User-Agent and header adjustments have been tested but did not resolve the issue.

Potential Technical Issues:
- Proxy Tunneling or Configuration errors.
- TLS/SSL Handshake mismatches (JA3 fingerprint discrepancies).
- HTTP Header inconsistencies.
- DNS resolution issues.

What We Are Looking For We are seeking a developer with proven experience in:
- Python / Node.js / PHP (Familiarity with backend scripting).
- Advanced Proxy Integration (Residential or Datacenter proxy protocols).
- HTTP Request Management (Header optimization, Cookie management, Session persistence).
- TLS Fingerprint management and SSL configuration.
- Root cause analysis and resolution of 403/429 HTTP error codes.

Task Requirements:
- Diagnose the root cause of the 403 error when using a proxy.
- Configure necessary network settings to ensure system stability behind the proxy.
- Implement optimizations for TLS/HTTPS compatibility if required.

Work Details:
- I will share relevant working files privately.
- This is a one-time debugging task (with the possibility of ongoing cooperation based on performance).