In an AWS environment utilizing AWS Organizations and AWS IAM Identity Center (AWS Single Sign-On), a security engineer is tasked with creating a custom permission set that includes an AWS managed policy and a customer managed policy. This permission set is intended to be used across multiple AWS accounts. However, when attempting to assign this permission set to an IAM Identity Center user who has access to multiple accounts, the assignment process fails. The security engineer, who has full administrative permissions and is operating in the management account, needs to resolve this issue. What corrective action should the security engineer take to successfully assign the permission set?