VBA & API authentication

agomezv It is not possible to get long-term access without using the OAuth app authorization flow. Apps can get long-term access by requesting "offline" access in the OAuth flow, in which case the app receives a "refresh token" that can be used to retrieve new short-lived access tokens as needed, without further manual user intervention. Note that you only need to do this once per account though, as the resulting refresh token does not expire.

You can find more information in the OAuth Guide and authorization documentation. There's a basic outline of processing this flow in this blog post which may serve as a useful example.