JS SDK: No "Access-Control-Allow-Origin" header is present on the requested resource. Origin "my website url" is therefore not allowed to access.

[Valarpirai]

I am using the JS SDK(dropbox-datastores-1.1.0.js). I have seen the following error in my console.
XMLHttpRequest cannot load https://api18.dropbox.com/1/datastores/put_delta. No "Access-Control-Allow-Origin" header is present on the requested resource. Origin "my website url" is therefore not allowed to access. The response had HTTP status code 504.

[Rich]

Moved to the API forum.

[Greg-DB]

A 504 response from the Dropbox API just indicates transient server issues on our side. This error response isn't specific to the API though and so doesn't have the right headers for use with JavaScript. Anyway, in this case you don't need to do anything special besides just retrying the request.