Between 1:22 AM and 4:13 AM PDT, customers experienced an increase in DNS resolution errors from EC2 instances in a single Availability Zone of the US-EAST-1 Region. This could have also impacted functionality of other services that use EC2, such as RDS, SageMaker, EMR, WorkMail, MSK, AWS IoT Analytics Service, Amazon ElasticSearch, Cloud9, AppMesh, Amazon Managed Blockchain, Glue, and AWS Transfer. The issue has been resolved and all DNS queries are being answered normally.