Hi Rafael,
The
NOT_AUTHORIZED error occurs when the user authenticating the request is not authorized to perform this operation. You will need to verify that the user making this API call has
Administrative access to the Manager account. If the user authorizing the API call doesn't have Administrative access, you will get the NOT_AUTHORIZED error. If that is the case, you could either ask the Admin on the account to upgrade the access level of the API user or use the credentials of a user with the required access level to make the API call. If you still encounter the error with an administrative access, please share the email address used to generate the client credentials along with the CID so that I can troubleshoot the issue.
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Thanks,
Milind, AdWords API Team