Elastic IP addresses could not be released.

Hello.

What was that Elastic IP address used for?
If you have rDNS configured, please reset the settings using the steps in the document below and then try deleting the Elastic IP address.
https://repost.aws/knowledge-center/ec2-address-errors

If you still cannot delete it, we recommend that you open a case with AWS Support under "Account and billing".
Inquiries under "Account and billing" can be made free of charge.
https://docs.aws.amazon.com/awssupport/latest/user/case-management.html