Issue: Python virtual environment creation fails
Solution: Install python3-venv: sudo apt install python3-venv
Issue: Node.js version incompatible
Solution: Install Node.js 16+: nvm install 16 && nvm use 16
Issue: Backend fails to start - "Address already in use"
Solution: Kill process on port 5000: lsof -ti:5000 | xargs kill -9
Issue: Database connection error
Solution: Check DATABASE_URL in .env, ensure SQLite or PostgreSQL is accessible
Issue: Blockchain connection fails
Solution: Start Ganache: ganache-cli -p 8545 or check BLOCKCHAIN_PROVIDER_URL
Issue: JWT token expired
Solution: Login again to get new tokens (15min expiry for access tokens)
Issue: Account locked after failed logins
Solution: Wait 30 minutes or contact admin to unlock
Issue: Rate limit exceeded (429 error)
Solution: Wait for rate limit window to reset (see X-RateLimit-Reset header)
Issue: CORS error from frontend
Solution: Check CORS configuration in backend/app.py
See Configuration Guide for detailed settings.