EC2 launch still fails with "Your request for accessing resources in this region is being validated" after receiving validation approval email

The error message you're encountering indicates that AWS is still processing the validation of your account for resource access in that region, even though you received a validation approval email. This situation can occur due to a timing delay between when the approval email is sent and when the validation is fully propagated across AWS systems.

Here are some steps you can take:

1. Wait a bit longer: There can be a delay between receiving the validation approval email and the actual completion of the validation process in the backend systems. Sometimes this can take a few hours to fully propagate.

2. Try a different region: If you need to launch instances urgently, consider launching in a different AWS region where you may not have this restriction.

3. Clear browser cache and try again: Sometimes clearing your browser cache or trying a different browser can help, as there may be cached session information.

4. Contact AWS Support: Since you've already received the validation approval email but are still experiencing the restriction, the best course of action is to reach out through the AWS Support Center at https://console.aws.amazon.com/support/. They can verify the status of your account validation and manually resolve any issues if the validation hasn't been properly applied to your account. When you add correspondence, mention that you received the validation approval email but are still seeing the error message.

This type of issue typically requires AWS Support to investigate the specific state of your account validation, as they have access to the backend systems that control these restrictions.
Sources
Troubleshoot Amazon EC2 instance launch issues - Amazon Elastic Compute Cloud

While it usually resolves within a few minutes, it can sometimes take up to four hours. However, there have been multiple reports of the process remaining stalled for over 48 hours, which matches your situation.

In this case, please open an AWS Support case, as previously advised.