After restarting instance This account is currently blocked and not recognized as a valid account.

Hi there... So for this, “I just restarted my instance now my state is stuck on stopped and getting an error (This account is currently blocked and not recognized as a valid account.) I created a case also now more than 20 hours but still no response my business totally relay on this please help me to solve this ASAP”,

I strongly lean towards the resource/account being blocked or suspended. They can check with the Account verification team to confirm any issues that are account related at - aws-verification@amazon.com or contact AWS Billing & Accounts team here - https://support.aws.amazon.com/#/contacts/aws-account-support/

Here is another useful doc they can refer to to address these kinds of issue - https://aws.amazon.com/premiumsupport/knowledge-center/sign-in-account/