Thank you for reaching out to Constant Contact API Developer Support. My team is here to assist outside software developers with questions about building into Constant Contact's API.
Sorry for any difficulty getting started with authorization, I know the process can seem a little daunting when first getting started.
The authorization code only has a lifespan of 5 minutes, so you'll want to make sure that you are exchanging it for your first token set within that period of time.
If this does not resolve the issue, there may be a problem with how the requests or key's settings have been configured, so if the issue persists, please feel free to email our team directly at email@example.com and reference case #30945726 with the API key that you are using to make the request, the full request(s) where you are receiving the response error (including URL, headers, timestamp, and request body), and the full response body so that we can so that we can better assist you in identifying the root cause of the issue.
*Please send the information requested above to us securely via email, rather than posting it directly in the forum, for privacy purposes. We look forward to assisting you.
Please have a look and let us know if you have any other questions!
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