Error handling

Error Code	Possible Causes	Resolutions
400 PRECONDITION_FAILED	The reader you are trying to delete with DeleteReader still has active entitlements.	Remove all entitlements from the reader, or use the force=true option with the DeleteReader`request.
403 PERMISSION_DENIED	The service account is not associated with the Google Cloud project you configured in Publisher Center. The service account lacks the required role for the method being called (e.g., a Subscription Linking Viewer attempting to update entitlements).	Verify that you have configured the correct Google Cloud project number in Publisher Center. If you are using Account Default Credentials (ADC) with gcloud auth application-default login command, ensure you have Service Account Token Creator role. Ensure the service account has one of the roles. Subscription Linking Admin Subscription Linking Viewer Subscription Linking Entitlements Viewer
404 NOT_FOUND	The specified publicationId or ppid doesn't exist.	Verify that the provided publicationId and ppid are correct and exist.