What role do Referer headers or CORS policies play in 403 errors, and how can they be managed or investigated in Postman?

1. **Referer Header:** Some APIs block requests if the `Referer` header doesn't match an expected domain, often for security reasons like preventing CSRF or direct access. While Postman typically doesn't send a `Referer` by default, if simulating a browser or a specific scenario, you might need to manually add it in the 'Headers' tab. 2. **CORS (Cross-Origin Resource Sharing):** CORS is a browser security feature. A server might be configured to deny requests from certain origins. Postman, being a desktop application, bypasses browser-level CORS policies. Therefore, a 403 in Postman is rarely a direct CORS enforcement issue. However, the *server's* underlying origin-based access logic could still return a 403 if it considers Postman's implicit origin unauthorized, even without a formal CORS preflight failure.