USER_PERMISSION_DENIED error when accessing a customer.

Hello, I'm starting to use Ads API, but stuck in the first place. My company has a main MCC where dozens of campaigns registered in. For the API use, i created a google ads id as a dev account, link it to the main MCC, create developers token in the MCC, and created OAuth credentials in th

getCampaigns.java returns an empty list. might be an account problem.

I encountered a problem while i was getting started to use Ads API. The getCampaings example is not working as i expected. I, my Company has an google ads MCC account, say ACCNT_A, that has several sub_accounts, and each of the sub-accounts has valid campaigns. And i created a dev account