Fix Rate Limiting for Public API Access 403 Error

I'm encountering a 403 error while trying to access a Public API. I've implemented some rate limiting measures, but they seem ineffective. Currently, I'm using user agent randomizing and proxies as the rate limiting method.

I need an experienced professional who can:
- Diagnose the issue with my current rate limiting measures
- Suggest and implement more effective rate limiting strategies
- Troubleshoot the 403 error and get me back on track with accessing the API

Ideal skills include:
- Deep understanding of rate limiting methods
- Experience with public API access
- Proficiency in troubleshooting API errors

I am looking to fix my existing code.