If you exceed the default maximum quota of accounts for your organization, then you receive the following error message:
"You have exceeded the allowed number of AWS accounts"
To resolve this error, request an increase to the maximum number of accounts in your organization. You can use the Service Quotas console or AWS CLI to request the increase.
Important: You must use the us-east-1 Region to access Organizations quotas from the Service Quotas console or AWS CLI.