Resolving EC2 Error: "Instance launch failed. This account is currently blocked and not recognized as a valid account."

(A Japanese translation is available here.)

The Issue Encountered

When attempting to create an EC2 instance, the following error occurred:

Instance launch failed. This account is currently blocked and not recognized as a valid account. Please contact ...

The details are shown in the image below.

When clicking the "Diagnose with Amazon Q" button next to the error message, a message appeared stating that "a support case needs to be created in the AWS Support Center," as shown in the next image.

Timeline

Here is the timeline of how I resolved this issue.

June 30, 2026

Opened a support case.

July 2, 2026

Received a response from AWS Support stating that "a root user password reset is required." The details are as follows:

Dear Customer,

Thank you for contacting us. We apologize for the inconvenience you are experiencing with EC2.
Upon reviewing your account, we found that certain services are currently restricted due to security concerns.

To enhance security, we kindly ask you to reset your root user password.

Resetting a Lost or Forgotten Root User Password:
https://docs.aws.amazon.com/en_us/IAM/latest/UserGuide/reset-root-password.html

Once you have completed this step, we will forward your request to the relevant department to lift the restriction.
Please reply to this case to let us know when it is done.

Thank you for your cooperation, and we appreciate your patience.

The support team did not provide specific details regarding the "security concerns." It might be because the AWS account was created a long time ago (March 6, 2018, which is eight years ago as of this writing), and I hadn't used EC2 since launching a few instances right after creating the account. Interestingly, other services like Lambda and S3 were working perfectly, meaning only EC2 was blocked.

On the same day, July 2, I reset the root user password and replied to support to inform them that it was completed.

July 3, 2026

Received the following update from support:

Dear Customer,

Thank you for your response and for completing the password reset.

We have forwarded a request to the internal team to lift the restriction on your account.
We will notify you as soon as there is an update. Thank you for your patience.
Please note that since this is handled by an overseas department, it may take a few days.
Thank you for your understanding.

Best regards,

July 7, 2026

Received the following update from support:

Dear Customer,

Thank you for your patience while we investigated this matter.

Our internal department has successfully lifted the restriction.
We apologize for the inconvenience.
Please try launching your instance again.

If you encounter any further errors, please reply to this case with the error message.
Thank you for your cooperation.

Following this notification, I attempted to launch an EC2 instance, and it succeeded without any issues.

July 8, 2026

Replied to support to let them know that the EC2 instance was successfully launched.
To avoid running into the same issue in the future, I asked support if they could provide specific details regarding the "security concerns" mentioned above.

On the same day, I received a response stating that they could not share specific details due to security policies:

Dear Customer,

Thank you for your update and reply.

Please be advised that due to our security policy, we are unable to provide specific details regarding what triggered the system or the exact criteria used for the restriction.

Generally speaking, AWS continuously monitors account security using various security systems to protect our customers' accounts.
When temporary restrictions like this occur, we ask users to perform security enhancements, such as resetting the root user password.
We appreciate your understanding.

To prevent similar issues in the future, we highly recommend following these security best practices:

https://docs.aws.amazon.com/en_us/IAM/latest/UserGuide/best-practices-use-cases.html

We apologize for the limited information we can provide, but thank you for your understanding.

July 9, 2026

Replied to support: "I got it. Thank you for clarifying that the details regarding the security policy and detection criteria cannot be shared."

July 14, 2026

Received a message from support stating that the case would be closed.

Dear Customer,

Thank you for your polite reply.

Since it appears you have no further questions, we will now close this support case.

Thank you for using AWS.

Conclusion

I am glad that I can now create EC2 instances successfully. Since AWS Support did not share the details of the "security concerns", my hunch that "it was because the AWS account was old (8 years old) and EC2 had been left unused for a long time" remains just a guess.