Thank you for reaching out to Constant Contact API Support.
Are you using "authoirzation_code" exactly? If so, it looks like you may just have a typo. Try authorization_code instead and let me know if you are still seeing this error. If you are, please send an email to firstname.lastname@example.org, and include a code snippet if possible.
Sincerely, David B. Tier II API Support Engineer
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