These two options use entirely different mechanisms to lookup the Heroku app by 1) git remote name 2) heroku app name.
When you say --app staging
you are looking up an app called staging
which you do not own, and getting a permission denied.
When you use the --remote staging
you are looking up the app attached to your git remote called staging
and it works.
The right way to use --app
is with --app your-app-name
, since staging
is not your app.