A company utilizes multiple AWS accounts, with DNS records managed in a private hosted zone on Amazon Route 53 in Account A, and applications and databases hosted in Account B. A solutions architect is tasked with deploying a two-tier application in a new VPC. To streamline the setup, a CNAME record set for the Amazon RDS endpoint, db.example.com, was established in the private hosted zone on Route 53. However, the application failed to launch, and diagnostics indicated that the db.example.com DNS name was not accessible from the EC2 instance. The solutions architect verified that the record set was correctly configured in Route 53. What steps should the solutions architect implement to address this DNS resolution issue? (Select two.)