我们的一些用户在浏览器控制台中收到此错误：
XMLHttpRequest cannot load https://d2ynz9y5qgba7.cloudfront.net/icons/instagram.svg.
No 'Access-Control-Allow-Origin' header is present on the requested resource.
Origin 'https://www.weld.io'; is therefore not allowed access.
这些是当前的标题：
Accept-Ranges: bytes
Access-Control-Allow-Methods: GET
Access-Control-Allow-Origin: *
Age: 21038
Content-Length: 1086
Content-Type: image/svg+xml
Date: Wed, 23 Mar 2016 10:00:12 GMT
Etag: "5cc3b790e15d7736b95880001521630b"
Last-Modified: Wed, 18 Mar 2015 10:20:32 GMT
Server: AmazonS3
Via: 1.1 8cdc69e06e564b9aef153cf0b52204b0.cloudfront.net (CloudFront)
X-Amz-Cf-Id: 0lD_0czYTm6i5f7RlURkG2dcQx_B252LC2GOu98anzHH1k1eaz2lmg==
X-Cache: Hit from cloudfront
如您所见，Access-Control-Allow-Origin确实存在。
我们还在CloudFront上“白名单”Origin。
这个问题可能是什么原因？