EC2 instances should be managed by AWS Systems Manager

How to fix it

In the console

Systems Manager → Fleet Manager → Account management → Configure Default Host Management Configuration

Enable Default Host Management Configuration

On

IAM role

The default, AWSSystemsManagerDefaultEC2InstanceManagementRole, which the console creates; other routes need it first

SSM Agent

3.2.582.0 or later, on an instance that uses IMDSv2 and can reach the Systems Manager endpoints

With the AWS CLI

aws ssm update-service-setting --setting-id /ssm/managed-instance/default-ec2-instance-management-role --setting-value service-role/AWSSystemsManagerDefaultEC2InstanceManagementRole --region <region>

With Terraform

resource "aws_ssm_service_setting" "this" {
  setting_id    = "/ssm/managed-instance/default-ec2-instance-management-role"
  setting_value = "service-role/AWSSystemsManagerDefaultEC2InstanceManagementRole"
}