I have been trying to download/extract the source code for an application in the google app engine. I found this more current post, How to download App Engine Source Code from Google Cloud Console?, but I do not see any files or folders in the staging bucket. My login is an owner of the project. I have also tried the appcfg.py commands but receive the authentication error below. Is this because this is deprecated? Or are there some other permissions my login requires?
<ApiError 401, Message: "Rejected by creds_policy: Permission 'auth.creds.useNormalUserEUC' not granted to app-engine-appserver@prod.google.com, because it satisfies none of the 3 rules granting that permission. (Policy {type=creds, id=/apps/framework/auth/v0/mapping0/80102d58-16e4-455f-bf24-13feb564b751}); RpcSecurityPolicy http://rpcsp/p/9aw5LWxoo9BLqcVKVlGreN0-Q5-wt_0mk2RWLjm140U com.google.security.context.validation.CredsPermissionException: Rejected by creds_policy: Permission 'auth.creds.useNormalUserEUC' not granted to app-engine-appserver@prod.google.com, because it satisfies none of the 3 rules granting that permission. (Policy {type=creds, id=/apps/framework/auth/v0/mapping0/80102d58-16e4-455f-bf24-13feb564b751}); RpcSecurityPolicy http://rpcsp/p/9aw5LWxoo9BLqcVKVlGreN0-Q5-wt_0mk2RWLjm140U ">