When trying to integrate adobe creative SDK in a web application I get error : "invalid_credentials"

I have followed the Web: Getting Started Samples and when the code AdobeCreativeSDK.init runs it loads http://ift.tt/2lcOB2C which invoke

http://ift.tt/2lLSoQS first with request method OPTIONS and then with request method POST, both returning status code 200 OK. The response to the POST request returns {"error":"invalid_credentials"} and I do not know why.

Any help will be appreciated.