yml file to do to resolve this issue?

Explanations:

While synchronizing the objects in the S3 bucket is important for ensuring that the latest files are uploaded, it does not address the caching issue in CloudFront. Changes in S3 might not be reflected immediately due to CloudFront caching. Therefore, simply synchronizing files without invalidating the cache will not resolve the visibility of updates through the CloudFront distribution.

Deleting previous website files and redeploying them does not guarantee that CloudFront will immediately reflect these changes due to its caching mechanisms. Even if the files are updated in S3, the cached versions served by CloudFront may still be used until they expire or are invalidated. Thus, this option does not effectively resolve the issue of stale content being served.

Invalidating the cache for the CloudFront distribution is the proper way to ensure that users see the latest updates. When the cache is invalidated, CloudFront fetches the updated content from the S3 bucket, allowing the latest changes to be served. This is essential for ensuring that the updates are reflected in the CloudFront distribution as expected.

Modifying the CORS policy of the S3 bucket does not address the issue of content not being updated in CloudFront. CORS policies are related to how resources can be requested from different origins, and changing them will not impact the cache behavior of CloudFront. Therefore, this option does not resolve the underlying issue of outdated content being served.