Maybe I'm missing something, but I don't understand how the OAuth flow works when adding contacts to a list from a "Email Signup" form on a website, where the user obviously doesn't have access to the Constant Contact account. The API method I'm looking at is here: https://v3.developer.constantcontact.com/api_guide/contacts_create_or_update.html
OAuth authentication just doesn't make sense in this scenario.
I am looking for this exact issue as well and I can't see how it is possible.
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