When working with an IAM Role authenticated EC2 Instance and
IMDSv2 set
to
Required:

Errors are displayed with either the Backup Wizard or Maintenance Plan Wizard:
Backup Wizard:

Maintenance Plan Wizard:

Use IMDSv2:*https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/configuring-instance-metadata-service.html