This incident has been resolved.

We've deployed a fix that should help to mitigate this issue. Be aware that there may still be intermittent problems for as long as AWS has an open issue. We'll continue to monitor the issue for any changes.

This issue appears to be related to trouble on AWS
see: https://status.aws.amazon.com/

We are investigating failures to store and retrieve native build artifacts. This can results in failed builds or errors when attempting to download a build from the dashboard.