• Login to Amazon S3 Console: https://console.aws.amazon.com/s3/home.
  • Locate your bucket, click on the same. On clicking, the right pane will show properties for that bucket. Expand Permissions, Click "Edit CORS Configuration" and update CORS to allow force.com.
  • Add following JSON snippet 
  • [
  {
    "AllowedHeaders": [
      "*"
    ],
    "AllowedMethods": [
      "PUT",
      "POST",
      "DELETE"
    ],
    "AllowedOrigins": [
      "*.force.com"
    ],
    "ExposeHeaders": [
      "ETag"
    ]
  },
  {
    "AllowedHeaders": [
      "*"
    ],
    "AllowedMethods": [
      "PUT",
      "POST",
      "DELETE"
    ],
    "AllowedOrigins": [
      "*.visualforce.com"
    ],
    "ExposeHeaders": [
      "ETag"
    ]
  },
  {
    "AllowedHeaders": [],
    "AllowedMethods": [
      "GET"
    ],
    "AllowedOrigins": [
      "*"
    ],
    "ExposeHeaders": [
      "ETag"
    ]
  }
]

    Or you can add in the following XML format

  • <?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
   <CORSRule>
      <AllowedOrigin>*.force.com</AllowedOrigin>
      <AllowedOrigin>*.visualforce.com</AllowedOrigin>
      <AllowedMethod>PUT</AllowedMethod>
      <AllowedMethod>POST</AllowedMethod>
      <AllowedMethod>DELETE</AllowedMethod>
      <AllowedMethod>GET</AllowedMethod>
      <ExposeHeader>ETag</ExposeHeader>
      <ExposeHeader>x-amz-meta-custom-header</ExposeHeader>
      <AllowedHeader>*</AllowedHeader>
   </CORSRule>
</CORSConfiguration>


  • For more info click here