We have created our own app. In first step creating app, we have choose "private app" ( One off Only my portal will get value out of this amazing app).
the owner of the app (firstname.lastname@example.org) has account administrator and sales administrator permissions in the account.
When the owner of the app or owner of the account tries to install app (https://app.hubspot.com/oauth/authorize?client_id=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx&scopes=contacts&redirect_uri=http://www.domain.com/hubspot/auth), we get a Uh oh! You do not have the correct role to grant these permissions. Please contact your administrator.
Our App ID is: 36676
Our Portal ID is: 596253
Thanks for your help!