Empty array in /v1/account

The scenario where the customer makes a GET request and receives 200 - OK but gets back an empty array happens when no account has granted access to this information.

jwt.io

You can observe this by decoding your token on jwt.io:

Notice how the empresas.btgpactul.com/accounts.readonly scope is requested, but the line where the claim with the company's CNPJ should be contains only "empresas.btgpactual.com/accounts":"".

This tells us the empty array happens because no account actually allowed the use of this service.

Resolution

Resolving this problem is very simple: in the authorization code flow, just select the company using the radio button as shown in the screenshot below: