Permission denied to `heroku fork` app but able to push code to same app

Question

I am able to execute something like git push heroku master with no problems but when I execute heroku fork -a heroku staging (where heroku is my existing app and staging is a new app I am trying to create) I get ' ! You do not have access to the app heroku.' and the fork does not initiate.

I am following the instructions at https://devcenter.heroku.com/articles/fork-app

I am trying to just make a staging environment and would like to use fork so I don't have to manually copy over config vars or DB data. Thanks.

EDIT:

Just found "Forking is only supported on production tier database plans. Follow these steps to upgrade from a starter tier (dev or basic) plan to a production plan." at https://devcenter.heroku.com/articles/heroku-postgres-fork. Looks like forking is not permitted on starter tier DB's. Does this statement mean you can't fork an app (heroku fork -a sourceapp targetapp) on a starter tier DB?

Answer 1

This question is answered in another thread- Forking my existing heroku app for multiple environments:

"staging should be the name of the application you are creating, not the name of the git remote. You need to pick a unique name. I typically use mysite-prod and mysite-staging as my application names."

Answer 2

Not sure on your question in your edit, but the first message means you don't have access to the app itself. I'd double check the credentials you're signed into the Heroku Toolbelt with.