A developer reports errors when trying to access a web application.

Comprehensive and Detailed Explanation From Exact Extract:

A 403 Forbidden error indicates that the request was understood by the server but is refusing to fulfill it due to insufficient authorization. The developer is attempting to call a protected API that requires valid credentials such as an access key and signature (often used in HMAC-based APIs), but the values appear as Postman variables (e.g., {{rapyd_access_key}}), which suggests they were not replaced with actual credentials.

This typically means that the request lacks proper authentication or authorization headers, or the keys/signature are incorrect or missing. The presence of access_key, signature, salt, and timestamp in the request implies the API requires authentication, but the variables were not resolved or valid.

Relevant Extract from CompTIA CloudNetX CNX-001 Study Guide — under “API Security and Authentication”:

“A 403 error typically results from failed authentication or lack of proper authorization. Developers must ensure that tokens or signatures are valid, not missing, and properly injected.”

Other options:

A. 404 is the code for a missing resource, not 403.

C. A firewall rule would block the request entirely (e.g., no response or a 0 status), not result in a 403 from the server.

D. HTTP redirection issues typically result in 3xx codes, not 403.