Issue 

• A public certificate was created and recorded in Route53, but validation failed after 72 hours. 

• Despite repeated attempts, the status remains in Pending. 

Cause 

• Because the DNS CNAME does not exist, ACM (AWS Certificate Manager) cannot verify the ownership of the domain. 

Resolution 

• When requesting an ACM certificate using DNS validation, ACM provides a CNAME record that must be added to the DNS configuration. ACM uses the CNAME record to verify ownership of the domain, and once the domain is verified, the certificate status updates from pending validation to success. 

• Reference 

  • Why is my AWS Certificate Manager (ACM) certificate DNS validation status still pending validation?
    https://aws.amazon.com/premiumsupport/knowledge-center/acm-certificate-pending-validation/