Application Cannot Invite Extrernal Users to Sharepoint

Question

We also have an automation that uses client credentials with Graph API to share particular files/folders in SharePoint with external users it does this by posting to the /invite endpoint on an objectId. Recently, we locked down our SharePoint and OneDrive permissions to only allow users of a particular security group to be able to share externally. This broke the automation as now it generates a noResolvedUsers error when calling Graph. We added the Enterprise Application associated with the client credentials. as a member of the security group which is allowed to share externally, but this still results in the noResolvedUsers error. When I add my personal account and use a delegated authentication everything works if I add myself to the security group, but with the client credentials it does not seem to identify the client credentials are associated with an authorized application?

Any ideas here?