I just got off a chat with an AWS agent:

"We are investigating reports of occasional DNS resolution errors. The AWS DNS servers are currently under a DDoS attack. Our DDoS mitigations are absorbing the vast majority of this traffic, but these mitigations are also flagging some legitimate customer queries at this time. We are actively working on additional mitigations, as well as tracking down the source of the attack to shut it down. Amazon S3 customers experiencing impact from this event can update the configuration of their clients accessing S3 to specify the specific region that their bucket is in when making requests to mitigate impact. For example, instead of "mybucket.s3.amazonaws.com" a customer would instead specify "mybucket.s3.us-west-2.amazonaws.com" for their bucket in the US-WEST-2 region. If you are using the AWS SDK, you can specify the region as part of the configuration of the Amazon S3 client to make sure your requests use this region-specific endpoint name."

I'm not OP, but I heard that unofficially from somebody who works at aws.

From the phonecall with our AWS TAM and support reps