Hi Shady,
The error is usually triggered if the user is not allowed to perform the mutate action. Could you please check the
access level for the email address used for generating the OAuth credentials? If you're still having an issue, could you please share the request and response logs without redacting along with the email address used for authentication, to check this further? You can reply back via
Reply privately to author option.
Thanks,
Bharani, Google Ads API Team

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