Troubleshooting CORS issues

If you encounter unexpected behavior when you access a container that has a CORS policy, follow these steps to troubleshoot the issue.

1. Verify that the CORS policy is attached to the container.

   For instructions, see Viewing a CORS policy.

2. Capture the complete request and response using a tool of your choice (such as your browser's developer console). Verify that the CORS policy that is attached to the container includes at least one CORS rule that matches the data in your request, as follows:

   1. Verify that the request has an Origin header.

      If the header is missing, AWS Elemental MediaStore does not treat the request as a cross-origin request and does not send CORS response headers back in the response.

   2. Verify that the Origin header in your request matches at least one of the AllowedOrigins elements in the specific CORSRule.

      The scheme, the host, and the port values in the Origin request header must match the AllowedOrigins in the CORSRule. For example, if you set CORSRule to allow the origin http://www.example.com, then both https://www.example.com and http://www.example.com:80 origins in your request do not match the allowed origin in your configuration.

   3. Verify that the method in your request (or the method specified in the Access-Control-Request-Method in case of a preflight request) is one of the AllowedMethods elements in the same CORSRule.

   4. For a preflight request, if the request includes an Access-Control-Request-Headers header, verify that the CORSRule includes the AllowedHeaders entries for each value in the Access-Control-Request-Headers header.