Intermittent Error: getaddrinfo ENOTFOUND "domain name" Issue in applications hosted in EC2

Errors in resolving hostnames can be dependent on the languages and libraries that are in between your code and the DNS server. A related post can be found for code running in Lambda: https://repost.aws/questions/QUwk5XuNTUTwOVlZdq0peZQg/aws-lambda-failed-with-https-request-getaddrinfo-enotfound

Can you share more detail about the language and libraries being used? And is this part of an HTTP call from your code?

Its unlikely but possible that too many DNS queries are being submitted and your EC2 is being throttled. To determine if this is the case see the following post which outlines how to troubleshoot: https://repost.aws/knowledge-center/vpc-find-cause-of-failed-dns-queries

Route53 as service does not have any issues reported, so the issue might be related to the route53 configuration or the ec2 instance.

From route53/DNS point of view, there are multiple reasons which can lead to intermittent DNS resolution such as below:

1. Misconfigured name servers at the registrar
2. Altered name servers at the hosted zone
3. Client's DNS resolver can't resolve the domain
4. Amazon-provided DNS server throttling the DNS queries
5. The domain URL resolves from the internet, but not from the EC2 instance

Please find below article which explains how to troubleshoot intermittent DNS failures: https://repost.aws/knowledge-center/partial-dns-failures