Question

A single-page web application hosted on a static object storage bucket makes JavaScript fetch calls to a REST API on a different domain. Users report that the page loads correctly, but the data never appears. The browser developer console shows the API requests failing with a message indicating the response was blocked by the same-origin policy, while direct calls to the API using a command-line HTTP client return valid JSON with a 200 status. What is the MOST likely root cause?

Accepted Answer

The API is missing the appropriate Access-Control-Allow-Origin response header for cross-origin requests

Answer

The API's TLS certificate has expired, causing the browser to reject the response

Answer

The object storage bucket's DNS record has not fully propagated to all resolvers

Answer

The API server's connection pool is exhausted, dropping the browser's requests