This may be due to Service Control Policies (SCPs) in place for specific accounts that are preventing full access to data feeds associated to those accounts.

This can manifest on the platform end by receiving the following API response:   

Aws::EC2::Errors::UnauthorizedOperation: You are not authorized to perform this operation.

The first step is to confirm that your account configuration is indeed showing a "Healthy" status.  Navigate to SETUP>ACCOUNTS>AWS and look at the right hand side for status: 

If the status is not Healthy, you will need to click on the banner and resolve any of the issues that are detailed in the popup that appears.  Otherwise, you will want to check whether the account is being derived by the platform. 

Navigate to ASSETS>AWS>EC2>INSTANCES and check the "Derived?" column (if it's not already present you can use the "Edit Columns" option at the top of the table to add it in):

If the "Derived?" box associated to instances in the account(s) in question is checked AND the account is "Healthy", then the missing information is most likely due to a SCP in place for that account.  SCPs essentially lock down access to specific regions within accounts which prevents the platform from accessing metadata associated to your infrastructure.

You will need to set an exemption for the region in the role configured in the platform so that proper data collection can take place.

For more information on SCPs and how they work, see:  https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_example-scps.html

"Example 6: Denies Access to AWS Based on the Requested Region" is a good section to reference regarding this issue.

NOTE:  The Technical Support team cannot assist in modifying SCP policies as they can have a significant impact on overall infrastructure