If you receive a 401 UNAUTHORIZED_ACCESS, the likely cause is that your authentication credentials were missing or incorrect. The Ads API requires the use of OAuth 1.0A and HTTPS and we strongly recommend that you use an OAuth library rather than trying to roll your own. If using a known library, we can help you with debugging; see here for some suggestions.
If you receive a 403 FORBIDDEN, this means that the request itself has been understood, but it has been refused or access is not allowed. You will receive a representative error message that should explain why you received a 403. Alongside an error message, there will also be an error code. You can have a look here to see what each error code corresponds to. For example, an error code of 64 means your account is suspended and is not permitted to access this feature.
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