Erroneous 503s. I would get a 503 on every call. Uploading a single file with a single call would immediately 503. I never once got a successful upload. I simply switched the endpoint URL and credentials over to AWS S3 and it worked first time so it was not my code (though I suppose it could have been an issue in the library AWS's node S3 client). My theory was the request was somehow malformed based on what DO was expecting and it was returning a 503 rather than a 400. But the request did work with S3.