Need a Backend Developer to Debug and Fix an Error in My App (FastAPI/Django)

I'm looking for an experienced backend developer to help debug and fix an issue in my application. The backend is built with Python (FastAPI/Django), and I need someone who can quickly identify the root cause of the problem and implement a reliable fix — not just a temporary patch. What I need help with: Investigate and reproduce the bug in my application. Identify the root cause (not just the symptom). Implement a clean, tested fix without breaking existing functionality. Explain what caused the issue so I understand it going forward.