Your company wants to use an S3 bucket for web hosting but have several different domains to perform operations on the S3 content. In the CORS configuration, you have added CORSRule AllowedOrigin for the following Domains. http://www.domainnamea.com, https://www.secure.domainnamea.com, and http://www.domainnameb.com. Following Domains, https://domainnameb.com and http://www.domainnameb.com:80, are not allowed to access the S3 bucket.
What could be the most likely cause behind the unexpected access behaviour of the domains?

Answer options:

A.Both request https://domainnameb.com and http://www.domainnameb.com:80 don`t match the allowed in configuration.
B.HTTPS must contain a specific port in the request, e.g.https:// domainnameb.com:443
C.There’s a limit of two origin sites per S3 bucket allowed
D.Adding CORS automatically removes the S3 ACL and bucket policies

Correct Answer: A
Option A is correct. The origin was configured as http://www.domainnameb.com, and a request was sent for https://domainnameb.com and http://www.domainnameb.com:80 instead of http://www.domainnameb.com. The exact syntax must be matched. In some cases, wildcards can be used to help the origin URLs.
Option B is incorrect. This is not required to allow an origin domain to be included, although it can be.
Option C is incorrect. The limit is 100.
Option D is incorrect. The ACLs and policies continue to apply when you enable CORS on the bucket.
Verify that the Origin header in your request matches at least one of the AllowedOrigin elements in the specified CORSRule.
The scheme, the host, and the port values in the Origin request header must match the AllowedOrigin elements in the CORSRule. For example, if you set the 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 don`t match the allowed origin in your configuration.
References:
https://docs.aws.amazon.com/AmazonS3/latest/dev/cors.html
https://docs.aws.amazon.com/apigateway/latest/developerguide/how-to-cors.html
https://aws.amazon.com/blogs/aws/amazon-S3-cross-origin-resource-sharing/