Your Initial AWS Sync Did Not Complete

When an initial AWS sync does not complete, this typically means that the Aimably StackSet (an AWS feature) cannot automatically run in member accounts of an organization. To resolve, you must enable trusted access for AWS StackSets between the managing account and its member accounts.

Enabling Trusted Access for StackSets

Sign in to AWS as an administrator of the management account and open the AWS CloudFormation console by clicking this link -  AWS CloudFormation Console

From the navigation pane, choose StackSets. If trusted access is deactivated, a banner displays that prompts you to activate trusted access.