We performed scheduled maintenance on our upload API and migrated requests to a new service. While the vast majority of upload API requests were serviced correctly, there were a small number of requests that returned an unexpected response between 14:00 ET and 17:00 ET. Specifically, requests that depended on Cross-Origin Resource Sharing (CORS) headers may have been affected.
At this point, all requests to the uploads API should be getting served normally. We will continue to monitor the upload API. Any customers who are experiencing unexpected responses should contact us.